Krakatoa is an active volcanic island in Sunda strait, between the island 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. The explosion was distinctly heard as far away as Perth in Western Australia, about 3,110 km away, and the island of Rodrigues near Mauritius, about 4,653 km away. The eruption of Krakatoa was equivalent to 200 megatons of TNT, about 13,000 times the nuclear yield that destroyed Hiroshima and Nagasaki at the end of the World War II.

In the years before the 1883 eruption, seismic activity around the volcano was intense, with

some earthquakes. Beginning 20 May 1883, three months before the final explosion, steam venting began to occur regularly from Parbuwatan. Eruptions of ash reached distance of 6 km and explosions could be heard in Jakarta 160 km away. Activity died down by the end of May, with no records of activity until mid June. Eruptions started again around 16 June, when loud explosions were heard and a thick black cloud covered the islands for five days. On 24 June an east wind blew this cloud away and two ash columns were seen issuing from Krakatoa.
On August 27, a series of four huge explosions almost entirely destroyed the island. The explosions were so violent that they were heard 3,500 km away in Perth, Western Australia and the island of Rodrigues near Mauritius, 4,800 km away. The pressure wave from the final explosion was recorded on barographs around the world. Ash was propelled to a height of 80 km.

The eruptions of the Krakatoa destroyed the ¾ of the island and destroy Danan and Parbuwatan Mountain. Another effect of this eruption is the tsunami and the decreasing of average global temperatures to 5 until 10 below in 10 until 20 years. Weather patterns continued to be chaotic for years and temperatures did not return to normal until 1888.

This eruption is said to be the greatest eruption that ever been recorded in history. The sound of the explosion is heard untill 4.600 km from the central of the eruption. The decreasing of the temperature was the most destroying effect of the Krakatoa eruption. Eruptions at the volcano since 1927 have built a new island in the same location, named Anak Krakatau. This island currently has a radius of roughly 2 kilometers and a high point around 300 meters above sea level, growing 5 meters each year.