Nemrut (volcano) inside the caldera, becoming the world's second largest caldera lake. Subsequent eruptions separated a small lake Ilı from Lake Nemrut. Nemrut volcano has an elliptical shape, its size at the base is 27×18 km, and its center contains 377.5 km of volcanic materials. The caldera of Nemrut is the largest in Turkey, the fourth largest in Europe and sixteenth largest in the world. Locals link the name of the volcano with the legendary ruler Nimrod, who is credited with the construction of the Tower of Babel. Turkish chronicles of the 16th century reproduce a local legend as follows: Eruptions of
Nemrut (volcano) average is 6–8 °C warmer than expected for a lake of its altitude. Nevertheless, it partly freezes in winter because of the small size and depth. Recent studies note the danger of possible eruptions. Nemrut is located in close proximity to Tatvan (distance 10 km, population: 66,000), Bitlis (population 52,000), Ahlat (population 22,000), and a number of smaller settlements. In total, about 135,000 people live in the potential eruption zone. The presence of more than 1 km of water in the caldera adds a risk of flooding, which may destroy Güroymak, a town of 15,000 people. The climate of the