Learn about the history of this wonder of technology through either a one-hour guided tour ($30) or half-hour power plant tour ($15). Open from 9 am-5 pm daily; last ticket sold at 4:15 pm. Parking fee: $10. www.usbr.gov/lc/hooverdam. 30 miles southeast of Las Vegas. Take US Highway 93 to Nevada State Route 172. 702.494.2517.