Kauhakō Crater, Molokai

Kauhakō Crater is a volcanic crater located in Kalawao County, Hawaii, United States. The crater was formed between 230,000 and 300,000 years ago, as the result of the eruption of volcano Pu'u' 'Uao. It is located in the center of the Kalaupapa Peninsula on the island of Molokaʻi, and has a diameter of 500 metres by 650 metres. Lake Kauhakō, located at the bottom of the crater, has the world's greatest depth-to-surface area ratio of a lake and is the fourth deepest lake in the United States. In 2011, the lake underwent an overturning event, causing hydrogen sulfide to float to the surface of the lake and lifeforms, including shrimp and plankton, to disappear. ()