42.9446°N, 122.1090°W.
Caldera lake in southern Oregon, occupying the collapsed summit of Mount Mazama which erupted catastrophically approximately 7,700 years ago in a VEI-7 eruption that ejected 50 km³ of material. The resulting caldera is 8 by 9.6 km and 594 metres deep — making Crater Lake the deepest lake in the United States and the ninth-deepest in the world. The lake fills to a depth of 594 metres entirely from snowmelt and direct precipitation; it has no inlet or outlet streams. Water clarity has been measured to 43.3 metres with a Secchi disk, among the highest readings recorded for any natural lake. Native Klamath oral history records the eruption itself, transmitted across approximately 7,700 years and matched to the geological event by archaeologist Robert Cooke and others.
The Klamath people remembered a mountain falling into a lake — and the lake matched their description seven thousand seven hundred years later when geologists got around to checking.