The East New Britain province of Papua New Guinea is lush and tropical. Mountain peaks and active volcanoes surround the town of Rabaul and Simpson Harbor. Built on an ancient volcanic crater, the harbor is one of the deepest in the region. For the same reason, some of most spectacular diving and snorkeling in the world can be found here. At Sub-Base, a shallow reef extends dramatically out from shore before dropping off into a crevasse rich with fish and other marine life.