Tema Reef
Cook Islands
Tema Reef, also called Tima Reef, is a submerged coral reef in the northern island group of the Cook Islands, 23 kilometres (14 miles) southeast of Pukapuka coral atoll. No coral or rock shows above water, but the sea breaks heavily over the reef. Tema Reef measures about 550 by 360 metres (1,800 by 1,180 feet), covering a shallow but submerged area of 0.16 square kilometres (0.06 square miles).
Data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).