Rabaul Caldera (Papua New Guinea)
This Pacific supervolcano demonstrated its power in 1994 when twin eruptions from Tavurvur and Vulcan vents destroyed Rabaul town. Though its last major event occurred 1,400 years ago, the caldera remains extremely active. Residents have rebuilt among the ash-covered ruins. Ships dock in the harbor while ash plumes rise nearby. The turquoise bay surrounded by steaming volcanoes creates a scene of unsettling beauty.