Along the Sawtooth Scenic Byway, Shoshone began as a mining supply town during Idaho’s silver boom and became a railroad center for south central Idaho, with notable historic buildings of native lava rock and an ivy-colored trail station. Mammoth Cave is a lava tube formed when a lava flow cooled quickly at its outer edges; discovered in 1902, the one-and-quarter-mile tube later served as a civil defense shelter during the 1950’s and is open for self-guided tours. Shoshone Ice Cave, discovered in 1880, supplied ice to Shoshone until 1900; it is a lava tube 110 feet underground, nearly 1,700 feet long, and 40 feet high, where seepage from the Wood River freezes into an underground glacier averaging sixteen feet thick. Sculptured Canyon reflects the grinding power of water and pebbles, with fast-flowing meltwater from the last ice age more than 7,000 years ago carving the Shoshone lava field basalt into rock structures and potholes. The Wood River mining rush began in 1879 with the discovery of lead and silver, and the Wood River Mines became Idaho’s foremost mining region, yielding nearly $60 million of lead and silver. Ernest Hemingway first came to Idaho in 1939, completed “For Whom the Bell Tolls” there, spent his last years in Ketchum, died in 1961, and was buried with his wife Mary in Ketchum Cemetery. Sun Valley Resort, framed by Bald Mountain, opened in December 1936 as America’s first destination ski resort, built by Averell Harriman of Union Pacific Railroad, and quickly drew movie stars, sports heroes, and other public figures. Pole Creek Ranger Station, built in 1909 by Ranger Bill Horton, is the oldest ranger station in the Sawtooth National Forest, and excerpts from Horton’s diaries recall early forest rangers hauling water, measuring and marking timber, fighting fires, and overseeing thousands of sheep trailed through the valley. Idaho 75 crosses Galena Summit at 8,701 feet, where Galena Overlook looks onto the glacially carved Sawtooth Mountains and Sawtooth Valley, and mountain streams form the headwaters of the Salmon River as it begins its 900-mile journey to the Pacific Ocean. The Sawtooth Fish Hatchery, operated by the Idaho Department of Fish and Game, opened in 1985 as part of a federal mitigation program for the lower Snake River dams to trap, spawn, and rear spring chinook salmon and collect steelhead trout eggs. Redfish Lake, framed by Mount Heyburn and Grand Mogul, is the Sawtooth’s largest alpine lake, more than 300 feet deep, home to red kokanee and sockeye salmon, and a gateway to a 218,000 acre wilderness with abundant camping, hiking, and backpacking.