Little Blue Lake

Little Blue Lake is a water-filled sinkhole (“cenote”) in the Australian state of South Australia, in the state's south-east in the locality of Mount Schank about 20 kilometres (12 mi) south of the municipal seat of Mount Gambier. It is notable locally as a swimming hole and nationally as a cave diving site. It is managed by the District Council of Grant and has been developed as a recreational and tourism venue.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).