The Black Canyon of the Gunnison River is one of the deepest, narrowest, and most inaccessible canyons in the United States. Very few explorers have ever traversed the 53-mile gorge in Gunnison and Montrose Counties. The canyon, one of the nation's wonders, has been the precipitous stage for an exciting history featuring Ute Indians, a narrow-gauge railroad, sensational explorations, and the construction of the Gunnison Tunnel—the first major Bureau of Reclamation project in history. The Black Canyon became a national monument in 1932 and a national park in 1999. Today it remains a crown jewel of Colorado's Western Slope.