Palau offers world-class diving with sea walls, sheer drop-offs, caves and an exuberance of marine life. Palau (or Belau) is a 100-mile long archipelago, southeast of the Philippines. It hosts around 20 dive centres that use mainly small speed boats. Many liveaboards also traverse her seas. Researchers estimate that approximately 41,000 divers visit Palau each year, of which around 8,600 come specifically to dive with sharks. Palau became a nation state as recently as 1994. It is soon to establish the world's first nation-wide marine reserve, designating its entire ocean territory as an underwater sanctuary. Palau is by a deep trench and attracts large pelagic species like silky shark, manta rays, bigeye tuna, marlin and swordfish.The wet season is May to November. March and April are the best time to see sharks, with fewer turning up in May, October and November. Current and temperature are the key environmental factors affecting shark numbers, with more sharks the faster the current and the cooler the water. Visibility, moon phase and number of divers in the water have little influence on the number of sharks sighted.