Mount Batur or Gunung Batur is a volcano on Bali. Mount Batur last erupted in 2000. It is a volcano inside an older, larger, volcano. The original eruption, about 30,000 years ago, is one of the largest known volcanic events on Earth. The volcano is now 1,717 metres (5,633 feet) high. There are many people — whole villages — living inside the caldera.