Second Thomas Shoal

Second Thomas Shoal, also known as Ayungin Shoal, Bãi Cỏ Mây (Vietnamese) and Rén'ài Jiāo, is a submerged reef in the Spratly Islands of the South China Sea, 105 nautical miles west of Palawan, Philippines. It is a disputed territory and claimed by several nations. The reef is occupied by Philippine Navy personnel aboard ship, the BRP Sierra Madre (LT-57), that was intentionally grounded on the reef in 1999 and has been periodically replenished since then.