Crater Lake National Park : Michelin's recommendations
The deepest lake in the United States at 1,932ft, and the seventh-deepest in the world, rests in the caldera of a collapsed volcano called Mount Mazama. Spectacularly ringed by mountains that stay snow-covered most of the year, this crystal-clear sapphire lake, 6mi in diameter, forms the centerpiece of Oregon's only national park, attracting hikers, geologists, naturalists and those who are simply compelled by the mysterious presence of an immense bowl of blue water.Glaciated Mount Mazama formed half a million years ago, possibly a contemporary of better-known Cascade volcanoes such as Mount Shasta or Mount Rainier, when a group of overlapping volcanoes began blistering up from the earth's surface. Likely the mountain grew as high as 12,000ft before its cataclysmic eruption just 7,700 years ago. More than 18 cubic miles of pumice and ash were hurled into the air, covering the surrounding valleys. The rest of the mountain then collapsed, creating a bowl-shaped caldera, 4,000ft deep and 6mi wide. Several more eruptions filled in part of the caldera with lava. Within 400 years the lake had filled with rain water, and with no inlets in the lake, precipitation and evaporation keep it at a constant level. The water is so clear that on some days objects are visible down to 115ft.