Krakatoa, a volcanic island wedged between the islands of Sumatra and Java in the southwest Pacific, exploded in 1883 with a force four times greater than the biggest nuclear bomb ever detonated. It could be heard thousands of miles away. Upwards of 40,000 people died in the explosion and the resulting 90-foot tidal waves. Smoke and ash caused spectacular sunsets worldwide, lowered the atmosphere’s temperature slightly, and may have caused the all-time record for rain in Los Angeles in 1884.

On the Volcanic Explosivity Index, the Krakatoa explosion is listed as a VEI 6, a very large and rare eruption. Though it’s popularly believed to be the biggest one in history, in fact several other volcanoes in recent centuries have unleashed comparable amounts of energy: Mt Pinatubo in the Philippines in 1991, Novarupta in Alaska in 1912, and Huaynaputina in Peru in 1600. The Hunga Tonga eruption of 2022 also is rated VEI 6, and its boom was heard in Alaska, 6,000 miles away.

The remains of Krakatoa, including a new island, Anak Krakatoa, that is rising amid the exploded remains, belongs to present-day Indonesia. The volcano continues to have periodic eruptions, though none yet as large as the 1883 explosion.