deep sinkhole
© People's Daily
Chinese researchers claim to have found the world's deepest underwater sinkhole, located near the hotly disputed islands of the South China Sea.

Also known as a blue hole, it measures 300.89 meters (988ft) in depth, far surpassing the previous record held by Dean's Blue Hole in the Bahama Islands, which is 202 meters deep.

Measuring 130 meters in diameter, the hole was discovered at a major coral reef near the Paracel Islands, which both China and Vietnam have claims on, as part of an exploration project which ran from August 2015 until June.

Known as blue holes for their dark blue color, such holes are presumed to contain deep cave systems - but to explore such depths would be dangerous for divers.

Instead, scientists at China's Sansha Ship Course Research Institute for Coral Protection explored the phenomenon using an underwater robot with a depth sensor attached, known as "VideoRay Pro 4," according to Shanghai Daily.

Over 20 fish species and marine organisms were also found in the upper levels of the hole but with almost no oxygen below 100 meters, no life was found.

Traditionally known as Longdong, or "Dragon Hole," locals have been calling the sinkhole the "eye" of the South China Sea, with some believing it is it is referenced in the 16th-century Chinese Classic "Journey to the West."