When it was built in 1929, this historic bridge was the only place to cross the Colorado River for 600 miles.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

It's safe—and permitted—to walk across these twin natural sandstone arches.

This creepy, abandoned cemetery is all that remains of a once booming mining town.

An improbable waterfall springs from an orange-white cliff face, tumbling into the headwaters of the Virgin River above Zion National Park.

The last SR-71 ever constructed.

The only ski tunnel in North America provides easy access to amazing snow and beautiful views.

Where unreadable addresses are read, 24 hours a day, seven days a week.

Within the former ghost town of Cisco is a carefully restored tiny town with one resident and its own art residency.

Once a menacing challenge for trailblazers, this trail is now the most scenic drive in Utah.

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

Electrical pylon in the shape of Disney's beloved mouse.

The abandoned train depot now doubles as a well-placed rest stop for those who take the road less traveled.

Few other hotels can rival the grandeur of the Castle in the Rockies.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

An architect's childhood fantasy treehouse made real.

The king of U.S. high points towers over every other peak on the continent.

An exotic wildlife habitat right off The Strip.

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

The site of Paul Revere's historic two lantern warning.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.