Description: If you asked almost anyone to describe a tropical island, they would likely mention palm trees and flat, white sandy beaches that stretch for kilometers: they would describe a coral atoll. Coral atolls are normally long, thin bars of white sand that rise just a few meters above sea level. The island or island group surrounds a hollow center where a volcanic peak once was. The atoll shown in this photo-like satellite image is the island of Tureia, in French Polynesia, about 930 kilometers northwest of Oeno Island and 1,120 kilometers northwest of Pitcairn Island, both in the Pitcairn island group. The beaches shown here get their light color from the calcium-rich skeletons of coral and other reef dwellers. The soil built on top of the reef supports limited vegetation including coconut palms, taro, and breadfruit trees, the strips of green shown here.