Coron Island is a wall of Late Triassic Coron Limestone - the
third-largest of the Calamian Islands off northern Palawan, 20 km long and rising to about
640 m at Mount Dalara. Some 70% of it is bare, swiftlet-haunted karst, and
hidden inside the rock are 15 lakes, three of them tidally linked to the sea. The most
famous, Kayangan Lake - often called the cleanest in Asia - and the thermocline-layered
Barracuda Lake sit in walled basins reached only by climbing over the ridge; the
Twin Lagoon hides a saltwater and a freshwater pool split by a single limestone wall.
The whole island and its fishing grounds are the ancestral domain of the indigenous
Tagbanua, formally titled to them in 1998, who hold several of the lakes sacred and
manage access to this day. Across the strait, the town of Coron on Busuanga sits below
Mount Tapyas and its 700-step stairway. The bay between them is a graveyard: on
24 September 1944 a US Navy air strike sank a fleet of Japanese supply ships sheltering
here, and their wrecks are now among the world's great dives.
Dive below the surface. Orbit the camera down through the water. No open
bathymetric service covers Coron Bay at this resolution, so the underwater relief is modeled
from distance-to-shore: pale turquoise sand over the fringing reef, deepening into the channels
where the wrecks lie. The lakes are too small for the 30 m elevation grid to resolve, so they
read as part of the karst above - look for them by their labels.