Leave the glitz of Las Vegas behind for a play day at Hoover Dam. Just 35 miles from the neon lights, this man-made wonder is the Goliath of engineering feats. Built in 1935, the huge bridge straddles the Colorado River, and marks the border between Arizona and Nevada. Drive across the dam to marvel at its precipitous vertical sheers and the pellucid waters of Lake Mead. Have vertigo? Then, simply cruise below it in a boat.