In honor of the U.S. National Park Service's 101 birthday last week, let's have a look at Crater Lake National Park in Oregon, photographed by an Expedition 13 crewmember on the International Space Station in 2006. Crater Lake is an ancient caldera and is part of the Cascades volcanic chain. The deep blue hue is typical of the 592 meter (1943 feet) deep Crater Lake. Water is lost only by evaporation and seepage, and replenished only by rainwater and snowmelt from crater walls. These processes help maintain minimal sediment and exceptional water clarity. The ecosystem is of high interest to ecologists because of its isolation from the regional landscape, and pristine quality. Credit: NASA #nasa #craterlake #nationalparks #parks101 #iss