Between 20 May and 21 October 1883, the volcanic island of Krakatoa began erupting, lasting more than 5 months. On 27 August, the island had its most significant eruption, which destroyed over seventy-percent of the island and its surrounding archipelago, the island collapsing into a caldera. The eruption of 27 August had an estimated volcanic explosivity index of 6, and is one of the deadliest and most destructive volcanic events in recorded history; the third explosion of that day, that occurred at 10:02 a.m., remains the loudest known sound in history.