Crater Lake was formed 8,000 years ago, after an alleged massive eruption caused Mount Mazama to collapse. The lake plunges nearly 2000 feet below ground, which makes it the deepest in the US and seventh deepest in the world. The Native American Klamath tribe has always called this lake a sacred site. According to one of their legends, the Chief of the Above World and the Chief of the Below World had a battle which led to the destruction of Mount Mazama. In earlier times, the tribesmen used Crater Lake in their vision quests and it is still considered a spiritual spot. The lake is now part of Crater Lake National Park and should be topmost on your travel list.