The 343 islands of the Republic of Palau are diverse in geological origin and include volcanic, low platform, high platform, and atoll types. The Republic includes the islands of Koror (the administrative centre and capital), Babelthuap (the largest island in terms of land mass, making up 78% of Palau’s land area), Angaur, Peleliu and several coral outer islands including Sonsorol, Tobi, Pulu Anna, Helen’s Reef and Merir to the southwest, and Kayangel to the north.