[4] Its sides rise steeply to the rim of the caldera, which is partially filled by a volcanic crater lake with a depth of 500 m (1,600 ft).

[5] The caldera was formed by a major eruption around 1,000 years BP, which left deposits up to 0.5 metres (1 ft 8 in) thick on islands over 40 kilometres (25 mi) away.

After being cast off the ship, Captain William Bligh navigated the overcrowded 23-foot (7.0 m) open launch on an epic 41-day voyage first to Tofua and then to the Dutch East Indies port of Kupang on Timor equipped with a quadrant, a pocket watch, sextant and a compass.

[8] The only casualty on this voyage was a crewman named John Norton who was stoned to death by the natives of Tofua, the first island they tried to land on.

In the March 1968 issue of the National Geographic Magazine, Luis Marden claimed to have found this cave and the grave of John Norton.

[10] Both findings were later disproved by Bengt Danielsson (who had been a member of the 1947 Kon-Tiki expedition) in the June 1985 issue of the Pacific Islands Monthly.

[11] In May 1943, a lifeboat containing 23 survivors from the Liberty ship SS Phoebe A. Hearst, which sank after being torpedoed by the Japanese submarine I19 on 30 April 1943, landed.

The crew survived on shellfish and coconuts until spotted by a Lockheed Hudson patrol aircraft of the Royal New Zealand Air Force and were picked up the following day by the US Navy YMS-1-class minesweeper YMS-89 and taken to Tongatapu.

[16]The island is the largest area of undisturbed Tongan tropical moist forests in Tonga, and was designated a national park in 2001.