9. Quilotoa Crater Lake – Ecuador
The Quilotoa Crater Lake is in Ecuadorian Andes, and was formed when a caldera got filled with water. The caldera has a width of 3 km. and was formed when the most western volcano of the mountain range in Ecuador collapsed, after a catastrophic eruption about 800 years ago. Since then, it has gathered water to form a lake of 250 m depth. The water is greenish because of the minerals.