In a remote part of Spain, a drought has revealed a mysterious monument that dates back thousands of years.

Image: Victor H. Jimenez Majuelo/EyeEm/Getty Images

As a record-breaking summer sears the land across Western Europe, water has become a scarce resource. And owing to the extreme heat, the Valdecañas Reservoir – which has dominated the landscape in the Spanish region of Extremadura for more than 50 years – is beginning to evaporate. But as the body of water starts to disappear, something incredible – not to mention mysterious – emerges from the depths below.

That secret was only revealed after weeks of a deadly heatwave that had affected countries such as France and Germany as well as Spain. And as the resultant drought transformed the land, emergency measures began to come into force. But while the cities and their inhabitants sweltered, the unexpected surprise in the reservoir reared its head.

So, what exactly did the water conceal? Well, thousands of years ago, a mysterious people lived in this now-remote part of the Iberian Peninsula. And while much of these individuals’ culture has since been lost to time, some relics nevertheless remain for those who know where to look. In fact, in this particular spot, locals have heard the legend of an ancient monument for many years – and now its moment in the spotlight has finally arrived.

Located in Western Spain, the Extremadura region has always had a hot climate with little in the way of rainfall. As a result, when the dictator General Franco set about developing the country in the mid-20th century, it may have seemed logical to construct a reservoir and dam in the area.

In any case, in 1963 workers flooded the countryside near the village of Peraleda de la Mata to create the Valdecañas Reservoir. And for decades, the facility helped to provide water in a region that is cursed with often-crippling heat. During the summer of 2019, though, a meteorological phenomenon created conditions that were even tougher than normal.

Beginning in June, a spell of atypically warm weather swept through much of Western Europe, with the mercury hitting record highs across the continent. And in this corner of Western Spain, that meant the onset of a terrible drought, with some farmers in the region likely to suffer severe financial hardship as a result of the heat and its consequences.

All across the region, the drought transformed the land into an arid expanse with little in the way of vegetation. And in Extremadura, even the vast reserves of the Valdecañas Reservoir were affected by the unusual weather. Yes, as the weeks crept by, the waters in the lake began to recede.

But while residents of the region likely fretted about their dwindling water supplies, there may have been something else about the situation that piqued their curiosity. It was said, you see, that a remarkable artifact lay hidden under the surface of the reservoir. Would the drought finally cause its secrets to be revealed?

According to locals, the source of this legend is a mysterious ancient monument known as the Dolmen de Guadalperal. Believed to have been created several thousands of years ago, the structure is built from approximately 150 stones that have been arranged in an oval pattern of some 16 feet in diameter.

Apparently, the rocks – known as menhirs – would once have held aloft a series of large flat stones laying horizontally, thus forming an enclosed chamber. Sometimes referred to as a dolmen, this space would have been reached via a long corridor stretching almost 70 feet. And at the entrance to the monument, a number of carvings would have been found.

Furthermore, according to Angel Castaño, who grew up in the area, the monument was built using stones from outside the local area. “The site would have been created over thousands of years using granite transported from kilometers away,” he told The Local in August 2019. Sadly, though, the exact method of the monument’s construction has since been lost to time.

But although it’s certainly mysterious, the ancient site is far from unique. In fact, its familiar structure has led some to dub it the “Spanish Stonehenge.” And as is the case with the famous megalith in Southern England, the dolmen is believed to have once been a center of both religious and memorial rites.

In fact, according to Castaño, the stones may initially have fulfilled a number of different roles. “Like Stonehenge, they formed a sun temple and burial ground,” he explained. “They seemed to have a religious but also economic purpose, being at one of the few points in the river where it was possible to cross, so it was a sort of trading hub.”

Despite its ancient heritage, however, the dolmen has remained relatively incognito over the years. Indeed, although it’s believed that the Romans were aware of its existence, the monument wasn’t officially “discovered” until the 1920s. At around that time, the German historian Hugo Obermaier began investigating the area.

While examining the site, Obermaier discovered a number of relics including ancient ceramics, axes and knives. In addition, he came across the remains of a settlement that is thought to date from the period when the monument was built. And along with the traces of ancient residences, the anthropologist also identified sharpening stones and mills.

For some reason, however, Obermaier’s findings weren’t made public until more than three decades later, in 1960. By that point, Franco’s mission to modernize Spain was well underway. And for the Dolmen de Guadaperal – which found itself at the heart of one of these new developments – this meant a rather undignified fate.

Three years after the publication of Obermaier’s work, in fact, the site of the dolmen was flooded in order to create the Valdecañas Reservoir. And just like that, a site that could have rivaled Stonehenge in terms of significance and appeal disappeared – taking its ancient secrets with it to a watery grave.

Yet even after it had vanished beneath the surface of Franco’s new reservoir, the dolmen wasn’t always completely hidden from then on. Over the years, you see, the water level would sometimes drop enough for the monument’s highest points to re-emerge. In fact, a drought in the 1990s dried up the region so much that the entire upper section of the dolmen could be seen.

And for the people who had grown up around the Valdecañas Reservoir, these occasional glimpses of the dolmen were enough to inspire a local legend. Then, when the hot summer of 2019 scorched the landscape of Extremadura, that myth soon collided with reality, as the ancient monument revealed itself in all its glory.

According to Castaño, who lives close to the monument, the reappearance of the structure was a spectacular sight. “All my life, people had told me about the dolmen,” he informed Atlas Obscura in September 2019. “I had seen parts of it peeking out from the water before, but this is the first time I’ve seen it in full. It’s spectacular, because you can appreciate the entire complex for the first time in decades.”

Then, with the dolmen exposed, curious onlookers were able to form their own theories about the mysterious monument. It was now possible, after all, to study the engraved menhir at the entry to the chamber. And while experts have historically accepted that the stone depicts a human and a snake, some other explanations have since arisen.

In Castaño’s opinion, for instance, the undulating line found on the rock represents not a snake but rather a body of water – specifically, the nearby Tagus River. Apparently, he believes that the marking mimics the path that the river once took through the region. And if Castaño is correct, the carving would be among the earliest maps in human history.

“It was intuition,” Castaño told Atlas Obscura in September 2019. “Before the area was flooded, the river had a strange bend that matched where the snake’s head was supposed to be. I rushed to consult an old map of the river, and I realized that the curvy line corresponded nearly 100 percent to the river’s path.”

However, some researchers have disagreed with Castaño’s bold hypothesis. Primitiva Bueno Ramirez from the University of Alcalá thinks, for example, that the lines are more likely to be a relatively common type of megalithic phenomenon. Having first examined the stones back in the 1990s, she believes that the carving has little to do with the local landscape.

“I appreciate his enthusiasm,” Bueno said of Castaño. “But from my archaeological understanding, I would say that the line is geometric and similar to ones found in megalithic art across Europe. In this case, it could be identified as a serpent.” Regardless, though, she acknowledged that further investigation was needed in order to make a positive identification.

But it wasn’t just experts such as Castaño and Bueno who found themselves drawn to the site, as the newly exposed dolmen soon became something of a tourist attraction. And despite the fact that visiting the site meant trekking for several hours in the baking heat, people still flocked to the remote location.

By early September, in fact, two different companies had begun operating boat tours that took tourists across the reservoir to see the monument. And with the challenging trek thus eliminated, visitor numbers to the area continued to grow. Yet while these developments have highlighted the site’s appeal, many observers are concerned about the adverse effect that such tourism may have on the stones.

You see, without anything in the way of barriers or security to protect it, the dolmen has been left exposed to interlopers. There’s the possibility, then, that enthusiastic sightseers may choose to touch and sit on the ancient stones. And such a prospect have raised concerns that the monument – which up to now has survived for thousands of years – may become irreparably damaged.

In addition, some onlookers have noted that the monument’s time underwater has left it in a state of disrepair. It seems that a number of the stones mentioned in Obermaier’s research have now moved, with previously elevated slabs now lying flat on the ground. Some pieces that were intact just decades ago, meanwhile, are now broken.

According to experts, the damage has been done because the stones that form the dolmen are made of porous granite – making them particularly defenceless to the process of erosion. And after seeing the state of the monument, Castaño’s group therefore began petitioning the authorities to move it to a dry location.

“It isn’t a difficult thing to move [the stones]; we have machinery now to do that,” Castaño told The Local. “Let’s just hope that there is the political will to move them while we can.” Not everyone agrees, however, that a hasty relocation is the right way of conserving the stones. Bueno’s view is that a rushed decision on the matter could prove even more detrimental in the longer term.

“Whatever we do here needs to be done extremely carefully,” Bueno told Atlas Obscura. “We need high-quality studies using the latest archaeological technology. It may cost money, but we already have one of the most difficult things to obtain: this historic monument. In the end, money is the easy part. The past can’t be bought.”

Despite Bueno’s concerns, however, many supporters have been pushing ahead with the campaign to save the stones. As of September 20, 2019, in fact, almost 50,000 people had signed a Change.org petition urging the Spanish authorities to take action. And according to Castaño, it’s vital that measures are taken soon.

“If we miss this chance, it could be years before [the dolmen is] revealed again,” Castaño told The Local. He believes, too, that the stones could provide a welcome economic boost for one of the country’s more overlooked regions. “There are already lots of reasons to come to this part of Spain, but there is very little tourism,” he pointed out. “This could be the kick-start that the region needs to bring tourism to the area.”

In fact, in Castaño’s eyes, the dolmen could become a thing of great value to the local community. “We grew up hearing about the legend of the treasure hidden beneath the lake, and now we finally get to view them,” he explained. “There certainly may have been treasures buried beneath the stones once upon a time. But for us now, the treasures are the stones themselves.”

Image: YouTube/Eberhard Karls Universität Tübingen

It should be known, though, that this is far from the only time that extreme weather conditions have inadvertently revealed an ancient site. Thousands of miles away in Iraq, for example, a drought in June 2019 affected the water in a Tigris River reservoir. And as the levels dropped, the remains of a Bronze Age palace were revealed.

Similarly, in 2018 a heatwave swept through much of the United Kingdom. Owing to the sweltering conditions, then, the quantity of water in the Burrator Reservoir on the wild expanse of Dartmoor in Southern England fell further than it ever had before. And in the process, relics of a long-forgotten 15th-century estate – known as Longstone Manor – emerged from the depths.

But it’s not just dwindling water levels that are capable of revealing these hidden histories. During that British heatwave, the resultant lack of plant growth also exposed traces of numerous past structures and settlements. And while some of these artifacts were merely a few centuries old, others originated all the way back to the Stone Age.

Meanwhile, over at the original Stonehenge, extreme conditions have helped to confirm long-held theories about the nature of the monument itself. Back in 2014 a spell of unusually dry weather had left the land parched, with the result being that there was now an outline of where missing stones had once stood. And using this natural blueprint, experts were able to determine that the structure had formerly consisted of a complete circle.

In Extremadura, however, specialists have been unable to predict how long it will be before the waters of the Valdecañas Reservoir rise once more – although it could be just a matter of weeks. And, currently, the fate of the dolmen remains undecided. Will Castaño succeed in his mission to secure a new lease of life for the monument? Or will it disappear beneath the surface for good?

And even when these questions are answered, there are other remarkable sights hidden away, waiting to be uncovered. Just take the incredible discovery that experts made in Ireland during the summer of 2018, for instance. Much as was the case in Extremadura, the abnormally dry weather revealed something that would otherwise have gone unnoticed – and it could just blow your mind.

Back in 2018 Ireland was subjected to unusually severe weather. While the island typically experiences moderate temperatures and lots of rain, this particular season actually brought about drought. But although the heat and lack of precipitation may have caused worry among the country’s farmers, they provided just the right conditions for historians to discover something special.

On July 10 of that year, Anthony Murphy and Ken Williams sent their drones hovering over Brú na Bóinne in the country’s east. This area is home to some spectacular ancient monuments – arguably the most famous of which is Newgrange. And owing to the Brú na Bóinne region’s historical significance, UNESCO awarded it World Heritage Site status in 1993.

Today, evidence of Brú na Bóinne’s past can be seen in the remains of tombs, stoneworks and henges. A henge is a sort of ancient modification to the land that consists of a circular bank and a trench. And such ditches were actually dug out within the earth berm – suggesting, then, that they weren’t created for protective purposes.

Yet while people are thought to have inhabited Brú na Bóinne for 6,000 years or so – perhaps even longer – the structures seen in the area today are thought to have been erected around 1,000 years after humans first settled there. This would mean that the remains’ origins date back to the Neolithic era of Irish history.

Image: Northern Ireland Environment Agency & Philip Armstrong via An Sionnach Fionn

The Neolithic era is best characterized as the concluding stages of the Stone Age. In Ireland, then, this period is said to have lasted from 4,000 B.C. up until around 2,500 B.C. And it’s thought that farming practices first started to develop on the island during this time.

Furthermore, some of the Neolithic constructions found in Brú na Bóinne date to as far back as the 35th century B.C. – making them older than even the pyramids of ancient Egypt. And just as with the pyramids, these Irish monuments suggest that the people who built them had a sophisticated grasp of mathematics.

The clearest indication of this ability is perhaps seen at the Newgrange monument. Newgrange is an elaborate tomb comprised of a broadly circular structure that encloses approximately an acre of land. There, a central alley lined with stone leads into a series of underground rooms.

And during the annual winter solstice, beams of sunlight travel through a passage in Newgrange to light up its interior. Nowadays, this event occurs some four minutes after the sun appears over the horizon; experts have calculated, however, that when the monument had been first built, the chamber would have been illuminated precisely at sunrise.

This in turn indicates that the people who designed Newgrange had quite astute understandings of both astronomy and math. It seems, too, that some individuals chose to demonstrate their artistic talents at the site, as Newgrange is also home to a variety of stone carvings that have been shaped in a number of different patterns.

But Newgrange certainly isn’t the only attraction to be found at Brú na Bóinne. You see, the area also plays home to the Neolithic monuments known as Dowth and Knowth. Like Newgrange, these two sites were both seemingly designed with sophisticated astronomical factors in mind, and the pair are also known today for their works of art.

In fact, the Brú na Bóinne region as a whole is said to possess one of the most extensive collections of Western European prehistoric stone art. And this shouldn’t be surprising given that there are around 90 other monuments in the area besides Newgrange, Dowth and Knowth.

Thanks to the ample evidence of its rich history, then, Brú na Bóinne has been a focus of contemporary archaeological works since 1960. In that year, a tomb within an area known as Townleyhall was first scrutinized. And although the monument turned out to be a relatively modest construction, it nonetheless seemingly sparked a great deal more archaeological interest in the region.

Indeed, over the subsequent decades, a series of additional archaeological probes have been undertaken throughout Brú na Bóinne. Numerous discoveries have been recorded in the process, too, with historians subsequently attempting to make sense of them all. And in more recent times, the works have been extended to even the edges of the area.

Yet although Brú na Bóinne has already told us a little about life in Neolithic Ireland, there are nonetheless still aspects of the period that remain obscure – meaning further study is necessary. And any new discoveries in the region may just help in this regard.

Journalist Anthony Murphy has certainly proven keen to investigate Brú na Bóinne. In fact, such is his passion for the region’s history that he frequently sends a drone up into the skies there – hoping, perhaps, to observe something new that may yet reveal more of the past.

And during July 2018, Murphy felt particularly compelled to investigate the lands of Brú na Bóinne. At the time, Ireland and the neighboring British mainland were experiencing unusually high temperatures and low rainfall. Plant growth was thus suffering under these harsh conditions, although there was at least one consequent benefit.

You see, hot and dry weather is actually extremely conducive to allowing so-called crop marks to stand out. Visible from above, crop marks are lines or patterns in the ground that indicate a construction has been buried beneath. As archaeologist Louise Barker explained to Wired magazine in 2018, “It’s like a painting that comes out into the fieldscapes.”

Certain prehistoric constructions – such as henges – would have been defined by man-made channels dug into the ground. And while these ditches would have been plugged up as the centuries passed, some of them may still retain extra nutrients and moisture upon which plant life depends.

And in extremely hot and arid conditions, plants will take their necessary nutrients from deeper underground than usual – meaning those that are positioned above nutrient-rich trenches will grow better than those that are not. Yes, while some flora will stay healthier and verdant, other examples will wilt and wither.

Furthermore, it appears that this is exactly what came to pass in the U.K. during the summer of 2018. In an area called Langstone in southern Wales, you see, an ancient farm was revealed by crop marks in the ground. And though it wasn’t initially clear when the farm had been in operation, the find was nonetheless significant.

Certainly, archaeologist Louise Barker seemed to be thrilled by the discovery. “We’re seeing new things with all of these crop marks,” she told Wired in the wake of the find. “We probably haven’t seen anything like this since the 1970s – the last time there was a really, really dry summer like this.”

When Anthony Murphy caught wind of new archaeological finds in Britain, then, he reasoned that the heatwave engulfing Ireland may reveal interesting etchings in the ground, too. So, over the course of a couple of days, he sent his drone over Brú na Bóinne.

“I was flying my drone over the Boyne Valley, as I do on regular occasions,” Murphy later wrote on his website Mythical Ireland. “I had it in the back of my mind that some previously unrecorded archaeological sites had been revealed due to the drought conditions in Britain – but I hadn’t the faintest expectation that I would find anything new.”

So, on July 9, 2018, Murphy sent his drone up to the sky in order to survey the ground below. By the end of this relatively short flight, however, he wouldn’t have much to show for his efforts beyond a small number of photographs. Indeed, on this occasion, his aerial survey had discovered little of particular interest.

Yet Murphy’s instincts told him that he needed to try again. “Something was nagging at me [the day after the first attempt],” he wrote on his website. “My own thoughts were niggling at me. ‘I will have to go out and fly again tonight,’ I said to myself. Gut feelings and all that. I knew it was important.”

On July 10, then, Murphy prepared to send his drone skyward once again. But just before he could actually do so, his friend Ken Williams suddenly showed up. Williams had actually been photographing Newgrange using his own drone, and the two men ultimately decided to work together.

Murphy was first to send up his drone, with Williams following suit shortly after. And the two machines were both fixed above a location with a series of intriguing features – although nothing earth-shattering. After some time, though, the power in Murphy’s drone began to fade, and so he landed it to swap batteries.

Then, with the drone ready to go once again, Murphy decided to send it towards a different area. And as he directed his airborne device in this particular direction, he noticed something strange. Beneath his drone, there appeared to be a circle etched into the ground.

Intrigued, Murphy lowered the altitude of his machine in order to get a better view of what lay below. And as a result, a series of other circles aside from the one he had initially sighted came into focus. This time, it transpired that Murphy’s drone had caught sight of something truly significant.

Murphy subsequently alerted Williams to his find, leading his companion to send over his own drone to the area. Careful not to crash their devices into each other, the two men set their drones to hover above the site, where they spent up to 15 minutes snapping photographs. And soon the pair were noting some additional features that they hadn’t previously spotted.

“Immediately to the west of the new henge was what appeared to be another large enclosure, and in the far northeast of the field [there were] some more circles,” Murphy later recalled on his website. “And close to the lake and trees – just to the north of them – [there was] a mottled landscape of dark and bright features.”

All in all, the two men were aware that they had managed to capture images of something significant. As a result, then, the pair both grounded their drones and subsequently sent out the photos of the markings to the archaeological community. And in turn, these people appeared to be just as enthusiastic about the discovery as Murphy and Williams were themselves.

In fact, Steve Davis, an archaeologist from University College Dublin, has implied that the find is potentially momentous. “This is internationally significant, and we now need to figure out what it means,” he told the BBC in 2018. “It has some characteristics that we’ve never seen before – for example, the very odd double-ditch sections that make up its circumference.”

“It’s one of a series of large monuments near Newgrange,” Davis continued. “We don’t know what the henges are for, but it’s thought [that] they were meeting places. The confusing thing is why there are so many [henges] in one area. Nowhere else in the world has so many in one spot.”

And fellow archaeologist Dr. Geraldine Stout gave her own opinion on the matter to the Irish Independent in 2018. She told the newspaper, “I think there was a whole series of facilities built for the pilgrims coming to Newgrange in prehistory. Generally, we believe these henge monuments were built up to 500 years after the main use of Newgrange.”

Image: National Monuments Service via World Heritage Ireland

Meanwhile, according to World Heritage Ireland, the warm conditions of summer 2018 brought about further discoveries. It seems, for instance, that the crop marks noted by Murphy and Williams were not the only ones to be recorded. During that period, you see, Ireland’s National Monuments Service decided to conduct a survey of its own from above Brú na Bóinne.

Image: National Monuments Service via World Heritage Ireland

What’s more, the pictures taken as part of this National Monuments Service search revealed features that had formerly been missed, while some added details were also acquired relating to established sites across Brú na Bóinne. Perhaps, then, the otherwise severe Irish climate conditions of 2018 were something of an archaeological blessing.

Image: National Monuments Service via World Heritage Ireland

At the very least, the plethora of visual data gathered during the prolonged dry spell seems set to keep the experts at the National Monuments Service busy with analysis for years to come. Already, the new aerial images of Brú na Bóinne have proved essential in both identifying new features in the area and gleaning fresh insights. And while there is naturally still some mystery about the region and its history, things may now prove a little clearer.

The sheer significance of Murphy’s discovery has not been lost on him, either. “In all honesty, it’s going to take some time to process this,” he wrote on his website. “Archaeologists are calling it a once-in-a-lifetime find.”

Murphy added, “Never in my wildest dreams did I think I would be involved in a revelation of this magnitude in the Boyne Valley – right there in the UNESCO World Heritage Site that has been under so much scrutiny from archaeologists for decades. Never in a million years would I have even thought it possible.”