Today, scientists understand that the hills are a volcanic range that was created hundreds of thousands of years ago during the Pleistocene era. When a series of eruptions hit the area between 560,000 and 350,000 years ago, they left behind a distinctive landscape that would later form part of the backdrop to the city of Rome.
Italy is, in fact, famous for its volcanic activity. Located where the tectonic plates of Africa and Eurasia meet, it’s home to more than ten explosive hotspots. However, while volcanoes such as Vesuvius and Etna are known for their deadly past eruptions, scientists have long assumed that Colli Albani poses little risk.
Indeed, until recently researchers had been unable to prove that Colli Albani had ever erupted at any point during human history. Naturally, then, they thought that the volcano was long extinct. However, recent observations have revealed that this may not be the case.