726 feet tall. 1,244 feet across. Holds back Lake Mead. Completed in 1935 — still one of the largest concrete structures ever built. The Hoover Dam tour is a 90-minute dose of historical context, actual engineering, and a view you can't get anywhere else on earth. It's 45 minutes from Vegas, and absolutely worth the drive.
$15, about 30 minutes. Takes you inside to see the generators. Best intro if you have kids.
$30, about 60 minutes. Goes deeper into the structure — ventilation shafts, maintenance passages. Adults only, slightly claustrophobic, fascinating.
The Mike O'Callaghan-Pat Tillman Memorial Bridge is the arch bridge 900 feet downstream of the dam. Walk the pedestrian path for the best aerial view of the dam. Free.
Combine Hoover Dam with a Lake Mead sightseeing stop or drive. The loop from the Strip takes 4 hours including the dam tour — add Valley of Fire State Park if you want a full day of desert scenery.