3. Crater Lake, Oregon
Formed nearly 8,000 years ago when Mount Mazama blew its top and left a 1,943 foot deep, smoldering caldera behind. Over time, the crater filled with rain and snowmelt. Crater Lake may be one of America’s deepest lakes, but it is also cut off from incoming streams and rivers.
The water remains extremely clear and sunlight penetrates the depths to around 400 feet down, making it a prime location for scuba divers. For those seeking a picture or two, wait until the sun goes down between Wizard Island and the Phantom Ship islands.