The Quilotoa Crater we see today sits within an extinct volcano and was formed during a massive volcanic explosion centuries ago. The crater was formed when the volcano's massive cone collapsed in on itself, leaving the crater in its place, which became a lake when it filled with water. The last major eruption here occurred in 1280 AD. This eruption was one of the most powerful recorded on Earth in the last 1000 years, with volcanic flow reaching all the way to the Pacific Ocean!