Pamukkale Travertine Terraces, Turkey

Pale blue pools fill the white travertine terraces of Pamukkale in southwestern Turkey, photographed in February with snow on the mountains beyond. Calcium-rich spring water built the terraces, which are a UNESCO World Heritage Site together with the ancient city of Hierapolis above them. Visitors walk barefoot and can wade in the shallow pools kept filled for them, while many other terraces are left dry.