In 1883 just off the coast of Jakarta, a volcano on the tiny island of Krakatoa exploded. It had been building up for months, and on the morning of August 27th, the volcano erupted for the fourth time, blowing apart the entire island. It spewed out over twenty five cubic kilometres of ash, pumice, and rock, created tsunami waves over thirty metres high, and overall caused over 36,000 deaths. The eruption caused a shockwave of energy to tear around the globe seven times, and it was measured by barometers for a full five days afterwards. This peak explosion was about thirteen times larger than the Hiroshima bomb, and the sound it made was literally heard around the world: people heard it clearly as far flung as Perth, 3500 kilometres away in Australia, and even 5000 kilometres away, police officials mistook the eruption for “the distant roar of heavy guns.” The sound is estimated to have been around 180 decibels—as loud as a rifle shot at point blank range, and loud enough to instantly kill all hearing tissue in the human ear. It’s believed that Krakatoa’s eruption was one of the loudest sounds ever generated on Earth, rivalled only by the eruption of Mount Tambora in 1815, and the Tunguska event of 1908, when a meteroid or comet fragment exploded in the air above Russia. No wonder Krakatoa is considered the most dangerous volcano in human history.