The McMurdo Dry Valleys are a row of snow-free valleys in Antarctica located within Victoria Land west of McMurdo Sound. The Dry Valleys experience extremely low humidity and surrounding mountains prevent the flow of ice from nearby glaciers. The rocks here are granites and gneisses, and glacial tills dot this bedrock landscape, with loose gravel covering the ground. McMurdo Dry Valleys, is a true natural wonder. Blood falls is an outflow of saltwater from the Taylor Glacier that is very rich in iron. The source of the outflow is a pool of saltwater hundreds of meters below the Taylor Glacier. As the water emerges from the glacier at its snout, the oxygen exposure causes its rich, distinctive 'red' color.