Krakatoa (Indonesian: Krakatau), also spelled Krakatau, is a volcanic island made of lava in the Sunda Strait between the islands of Java and Sumatra in Indonesia. The name is used for the island group, the main island (also called Rakata), and the volcano as a whole.
The best-known eruption of Krakatoa culminated in a series of massive explosions on August 26–27, 1883, which was among the most violent volcanic events in modern and recorded history. With a Volcanic Explosivity Index (VEI) of 6, the eruption was equivalent to 200 megatons (MT) of TNT—about 13,000 times the nuclear yield of the Little Boy bomb (13 to 16 kT) that devastated Hiroshim, Japan during World War II and four times the yield of the Tsar Bomba (50 MT), the largest nuclear device ever detonated. (Information provided by wikipedia.org)