How Volcanoes Work

 Image Described in Caption
 Santorini Island Group -- The large, ring-shaped island of Thera encloses most of the caldera, with the smaller island, Therasia, in the foreground. The town of Fira, and adjacent villages, appears as a small white layer on the central rim of the caldera. The darker young volcanic islands of Palea and Nea Kameni in the center of the caldera. Coutesy of Birke Schreiber (copyright: Hankensbuettel, Germany -