Krakatau, or Krakatoa, a volcanic island in Indonesia that was virtually destroyed in 1883 by one of the world's most violent eruptions. Krakatau was seven miles (11 km) long and four miles (6.4 km) wide, and consisted of three volcanoes up to 2,600 feet (790 m) high. During August 26-27, the island erupted in a series of explosions that destroyed the northern two-thirds and created a cavity as much as 900 feet (270 m) below sea level. Only a portion of one of the volcanoes, Rakata, remained.

The most violent eruption occurred on August 27. It was heard nearly 3,000 miles (4,800 km) away; ash clouds rose to a height of 50 miles (80 km); and dust darkened a wide area for several days. Along the nearby coasts of Java and Sumatra, a tidal wave up to 120 feet (36 m) high destroyed several hundred towns and killed some 36,000 people, mostly by drowning.

Krakatau resumed activity on the ocean floor in 1927 and emerged from the sea in 1952. The new cone, now some 400 feet (120 m) high, is called Anak Krakatau (child of Krakatau).