In this March 29, 2014 file photo, a Chinese Coast Guard ship attempts to block a Philippine government vessel as the latter tries to enter Second Thomas Shoal in the South China Sea to relieve Philippine troops and resupply provisions. While the global economy will dominate at the summit of the Group of 20 industrialized and emerging-market nations, politics and security issues form the backdrop to the gathering of world leaders in the eastern Chinese city of Hangzhou.

Of all the potential flashpoints in the contested South China Sea, none is more nervously watched today than Scarborough Shoal, a large coral atoll with a reef-rimmed lagoon. It encompasses 58 sq mi (150 sq km) and lies less than 150 miles (241 km) from the Philippines’ coast.
Observers have long suspected that China wants to build a militarized island there, and last week the Philippines defense ministry distributed pictures of what it said were Chinese vessels gathering in the area that could become involved in such activity.

http://qz.com/775382/all-eyes-are-on-the-scarborough-shoal-the-reef-rimmed-lagoon-that-would-allow-beijing-to-control-the-south-china-sea/