This holiday resort by the Baltic Sea was meant to be largest the world had ever seen. But a sinister past ensured that the guests never came.

A picturesque German island plays host to one of the longest building complexes in Europe – a structure that straddles almost three miles of coast overlooking the Baltic Sea. The enormous edifice is known as the “Colossus of Rügen,” and its identical windows and balconies stretch on for as far as the eye can see. What’s more, this grand yet forsaken facade masks an aspect of the darkest period in European history.

The massive construction that still dominates the landscape here was in fact once intended to be the biggest holiday resort in the world; indeed, it was built to cater for as many as 20,000 visitors at once. Alas, though, history had very different designs in store for the imposing complex.

Known as Rügen, the island on which the facility lies is located just off the coast of Pomerania in the north of Germany. This piece of land in the Baltic is roughly 30 miles long by 20 miles wide, and its expansive beaches, cliffs and scenic vistas have helped make it a popular tourist destination for many years.

Most visitors today stay in the kind of quaint holiday apartments or hotels that you’d expect to find on an enchanting island for vacationers. But if this complex had proven to be a success in the late 1930s, it would have represented a decidedly different form of accommodation.

It was the idea of a German politician named Robert Ley, who wanted to recreate the concept of affordable holiday camps – such as the U.K.’s Butlins resorts – in his own country. The plan was to create a venue for beachside holidays that was accessible even to low-paid workers, thus helping create a happy and content workforce.

To determine the design of this new resort, then, a competition was held. And, as this was an era in which the Nazi Party held sway in Germany, Albert Speer, Hitler’s foremost architect, oversaw the contest.

The winner was one Clemens Klotz. His design for eight monolithic buildings, located just 500 feet from the shoreline, would offer easy access for those wishing to enjoy a relaxing swim.

In 1936 construction on the complex, known as Prora, began. Moreover, for the next few years nearly all of the Third Reich’s construction resources were poured into the project. Almost 9,000 people worked on it in some capacity.

The buildings were constructed so that each room would offer residents a view of the Baltic Sea. Essential facilities, meanwhile, were located on the other side, with shared bathrooms positioned on each floor.

Hitler had big plans for Prora. As well as creating what he hoped would be “the most mighty and large” vacation resort ever built, he planned to add grand touches such as a hall with the capacity to accommodate all 20,000 visitors at once.

The Nazi Party’s leisure organization, Kraft der Freude – which translates as “strength through joy” – intended Prora to be the first of a series of similar resorts rolled out across the country. They hoped that affordable vacations would encourage Germans to support them. The buildings would be used as backup military facilities in the event of war.

The design for Prora was a popular one at the time, and in 1937 it scooped a Grand Prix award at the Paris World Exposition. But despite such accolades, the resort would never get to reach its glory days.

In 1939 Europe was braced for the start of World War II and construction on Prora ground to a halt. Workers were directed elsewhere and the resort remained an unfinished shell. Ten thousand rooms suddenly sat empty, waiting for guests that would never come. The completed structure stretched for nigh-on three miles along the coast.

During the war the complex saw sporadic use. When Allied Forces rained down bombs on Hamburg some citizens took refuge there. Later, refugees from East Germany and female members of the Luftwaffe were housed at Prora.

In 1945 victorious Soviet forces established a base at Prora and remained there for a decade. Then when the Soviets left, they stripped everything of value from the buildings, leaving them in an even more sorry state than before.

The newly formed German Democratic Republic’s National People’s Army then took possession of the buildings, and they remained there until German reunification in 1990. As various military units and training facilities moved in and out over the years, Prora’s purpose as a vacation resort seemed to slip further and further away.

It wasn’t until 1993 that the complex was abandoned for good. With the exception of one block that was used as a museum, a gallery space and a youth hostel, the rest of the resort began to slowly decay.

However, things may finally be on the up for the vacation destination that never was. In 2004 a decision was reached to sell the site as individual lots rather than one whole – and the offers began to trickle in.

Blocks one and two in the eight-block complex were sold to a company that planned to convert them into accommodation and shops. Block five, meanwhile, was earmarked as the location for a new youth hostel that finally opened in 2011. It now promotes itself as the longest youth hostel in the world.

In 2015, more than three quarters of a century after Prora was built, the first tenants moved into the apartments built within the resort’s walls. For the new residents, the promise of affordable living by the ocean seems to outweigh whatever sinister feeling might be left over from the ghosts of the buildings’ past.

But is Prora the only seaside resort to have succumbed to such a dismal fate? Well, the Kupari Tourist Complex in Yugoslavia was once a lavish vacation destination frequented by the country’s elite. But today the only visitors to the place are those who are drawn in by a morbid fascination to explore the now-skeletal structure – and the sinister past that it’s hiding.

These hallways once echoed with the steps of esteemed guests, but now they lie empty and silent. The grand facades of buildings are pockmarked with bullet holes, while nature climbs in slowly through the cracks. What could have caused this once-popular resort to be abandoned to such a dismal fate? Let’s find out and take a trip back in time.

On a beautiful bay in the south of what is now Croatia lies the village of Kupari. Close to the city of Dubrovnik and boasting some of the country’s best beaches, it seems like the perfect spot on which to build a holiday resort.

The Yugoslav People’s Army certainly agreed. Back in the 1960s, the region was under the government of the Socialist Federation of Yugoslavia and its leader Josip Broz, known as Tito.

Under Tito’s orders, work began on a tourist resort in Kupari. It was intended as a place where the military elite of the country could retreat to with their families for some rest and relaxation.

The site already had one building, the Grand Hotel, which had been constructed in 1920 by a Czech investor. Then, much later, in 1965, this was followed by the first purpose-built structure – the Goričina I Hotel.

It must have all been a success, too, because over the years three more structures were built around the resort: the Goricina II Hotel, the Kupari Hotel and the Pelegrin Hotel. What’s more, in 1979 the Grand Hotel was renovated, bringing the total number of bedrooms at the Kupari Tourist Complex to more than 1,500.

In addition to these hotels, the complex also boasted a campground with enough space for another 4,500 guests. Furthermore, there was even a luxurious villa where Tito himself would come to spend his vacations.

So it was that for more than 25 years the resort played host to the cream of Yugoslavian society. But history had some big surprises in store, and the summer of 1991 saw everything change.

Since the 1970s Croatia had enjoyed a certain level of autonomy within the Socialist Federal Republic of Yugoslavia. By the early 1990s, though, most of the Croats living in the region wanted to split completely and become an independent country.

Nevertheless, the area was also home to a large population of Serbs who wanted the region to remain part of the federation. After the end of the Cold War, then, tensions began to grow.

In 1990 a Croatian Parliament was formed and a new constitution issued. Moreover, although Serbs were a majority in Yugoslavia as a whole, they were a minority within Croatia. Many of them were therefore concerned about the effects that further autonomy would have on their rights there. Things were about to spiral out of control.

Fueled by propaganda from both sides, ethnic hatred subsequently escalated into a full-scale war between the Serbian-led Yugoslav People’s Army and the Croatian military forces. And while Croatia declared itself independent in June 1991, the conflict would rage for another four years.

By the end of 1995, then, the war was over, and Croatia had emerged victorious, at least on paper. However, 20,000 people had died, and much of the country was in ruins – not least the Kupari Tourist Complex.

Despite looking like paradise, the resort had suddenly found itself at the center of a war zone. Yes, during the conflict, although some Croatian forces were stationed there, the Yugoslavian warships that approached from the Adriatic Sea vastly outnumbered them.

Consequently, in October 1991, the Yugoslavian People’s Army regained control of the area. However, fighting had reduced the complex to a ruin – and the hotels were furthermore stripped of valuables and the buildings burned.

After the war, the resort was also briefly used as a base for the Croatian Army – before they too left in 2001. By then, of course, the buildings were ghosts of their former selves, war having made a mockery of this once-luxurious locale.

Compounding matters, for the intervening 15 years, the once-grand Kupari Tourist Complex has been left to slowly decay. Nature has begun to reclaim the land, with trees laying roots where guests would once have walked.

Meanwhile, times have changed in Croatia, and the area around Dubrovnik is now a hotspot for vacationers from around the world. In fact, the ruins of the resort have themselves become something of a magnet for those seeking to explore the country’s turbulent past.

“I heard about this place and the chance to see the effects of war and I just had to come,” one British tourist told The Dubrovnik Times. “This might be the last chance I have to experience the horrors of war, and I want to take as many photos as possible.”

However, things are on the move again. In 2016 work began to transform the Kupari Tourist Complex into a five-star Marriot hotel. Yes, while the listed Grand Hotel will remain, the rest of the complex is set to get a major facelift.

It’s certainly true that the new plans for the site are more in keeping with the modern image of Croatia as a vacation paradise rather than the scarred location of a bloody war. Even so, there are many who will lament the passing of this site in its current form. It will be the loss, after all, of a significant, haunting monument to the country’s struggle for independence.