Rising to 3,849 feet in elevation, Mount Diablo dominates the foothills and offers unobstructed views. On a clear day, its summit provides views over 200 miles in all directions, from the Sierra Nevada to the east to past the Golden Gate Bridge to the west. The mountain has long been a destination, and surveyors used it as the starting point for mapping much of California. By 1874, horse-drawn carriages traveled on newly constructed roads to carry tourists to the top.