Crater Lake in Oregon. This lake was created by a volcanic explosion which blew the top off of Mount Mazama. Now it is one of the deepest lakes in the world. When the water is perfectly still, the lake has a vivid deep blue color to it.

This was taken with a Nikon D90, Nikon AF-S DX NIKKOR 16-85mm f/3.5-5.6G ED VR, with slight post-processing in Adobe Lightroom 3.