Hoover Dam

One of the defining engineering monuments of the American century: a 726-foot concrete arch-gravity dam wedged into Black Canyon on the Colorado River, straddling the Nevada–Arizona state line about 45 minutes southeast of Las Vegas.

Built between 1931 and 1936 at the depth of the Great Depression, it employed some 21,000 workers and was finished more than two years ahead of schedule. The dam tamed the Colorado, created Lake Mead — the largest reservoir in the United States by capacity — and still supplies water and hydroelectric power across Nevada, Arizona and Southern California. It is a National Historic Landmark, and the Art Deco detailing is worth slowing down for: Oskar Hansen's winged bronze figures at the Nevada memorial, the terrazzo floors laid with Native American motifs, the sculpted intake towers rising out of the water.

What there is to do

• Walk the crest for free, crossing between Nevada and Arizona on foot — the upstream and downstream views are the single best free thing here
• Visitor Center with exhibit galleries, a documentary film and an observation deck
• Power Plant Tour: elevator ride 500 feet down into the rock to the Nevada generator hall and a diversion tunnel
• Guided Dam Tour: the deeper option, taking in tunnels and inspection galleries inside the dam itself
• Mike O'Callaghan–Pat Tillman Memorial Bridge: park at the trailhead and walk out onto the pedestrian walkway for the classic head-on view of the dam face, roughly 900 feet above the river

Practical notes

• The dam roadway is open daily from early morning to evening; the Visitor Center runs roughly 9:00–17:00 and closes Thanksgiving and Christmas
• The Power Plant Tour can be booked online; the Guided Dam Tour is sold on-site only and often sells out by mid-morning, so arrive at opening if it matters to you
• Paid parking garage on the Nevada side, with free lots further out on the Arizona side involving a longer walk
• Security screening at the entrance — expect delays on summer weekends
• US-93 no longer crosses the dam itself; through-traffic uses the bypass bridge, so you need to take the Hoover Dam Access Road exit deliberately
• Summer afternoon temperatures regularly clear 40 °C with almost no shade on the crest; morning visits are far more pleasant
• Reachable by bike or on foot from Boulder City via the Historic Railroad Trail, which runs through five original construction-era tunnels