The Transylvanian Basin in Romania stands out in brilliant green in this satellite image. Near the top of the image, the hilly, forested basin is tucked in between the Carpathian Mountains, running northwest-southeast, and the Transylvanian Alps, running west-east. To the right of the image is the Black Sea. The large patch of turquoise water in the Black Sea is a large phytoplankton bloom. At the bottom of the image, the Aegean Sea is ringed by Greece (left) and Turkey (right). Photo courtesy of NASA.