UN System-Wide Earthwatch: Tonga - Environmental information and statistics, including details for individual islands in the group. - http://islands.unep.ch/CKY.htm
Metis Shoal, Tonga - Michigan Technological University Volcanoes Page. A new island in the Tonga chain created by a 1995 volcanic eruption. Photographs. - http://www.geo.mtu.edu/volcanoes/new.zealand/metis/