Underwater EruptionWhitecaps churn in the Atlantic off West Africa as an underwater volcano erupts off Spain's Canary Islands on Monday. (See how the Canary Islands fared in an independent ranking of island destinations.)Since last week, the volcano has been spewing gas and fragments of smoking lava, staining the ocean surface green and brown, as seen above.Spanish authorities have closed a port on Hierro island (map), ordered ships away from the island's village of La Restinga, and banned aircraft from flying over the island's southern tip, according to the AFP news service.Six hundred residents living at the port were evacuated Tuesday.(See "Pictures: Giant Undersea Volcano Revealed.")

Photograph by Desiree Martin, AFP/Getty Images