Summertime above the incomparably blue waters of Oregon's Crater Lake, at 1,949 feet (594 m) the deepest lake in the United States. The lake fills the bottom of a caldera, formed some 7,700 years ago when the Mount Mazama volcano collapsed. The island in this shot, the Phantom Ship, is one of two in the lake, the waters of which derive entirely from rainwater and snowmelt. And yes, it really, really is that blue.
