Boulder City, NY visit to Hoover Dam,

It’s never been easier to visit this 75-year-old colossus, which provides 20 million residents of California, Nevada, and Arizona with water and 1.3 million with hydroelectricity. Some new engineering is now helping the flow of the near-million annual visitors: a four-lane, 1,900-foot-long Hoover Dam bypass bridge. This bridge is the second-highest in the nation, perched at almost 900 feet above the rushing Colorado River. Avoid the intense summer heat (as high as 110 degrees) by planning your visit during January or February, when temperatures hover in the low 60s. But be sure to arrive by 3 p.m. to tour the dam itself; visitors aren’t allowed to the top of the facility after dark, which comes as early as 4:30 p.m. during that time of year.