Crater Lake lies inside a caldera created 7,700 years ago when the -high Mount Mazama collapsed following a large volcanic eruption. Over the following millennium, the caldera was filled with rain water forming today's lake. The Klamath Indians revered Crater Lake for its deep blue waters. In 1853, three gold miners found the lake. They named it Deep Blue Lake, but because the lake was so high in the Cascade Range the discovery was soon forgotten.