The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

The Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.

This constitutionally sound Muffler Man harkens back to the days these attractions were a must-see.

This rusted car found in Petrified Forest National Park's Route 66 exhibit may be the most photographed abandoned car in the country.

See massive fossils that are over 200 million years old in northeastern Arizona.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A second generation sun-powered marvel lights up the night.

A collection of old shoes in the middle of nowhere.

The old Route 66 town straddling Texas and New Mexico died along with the Main Street of America.

A sign at the end of the Santa Monica Pier marks the traditional end of the legendary American highway.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

A museum devoted entirely to the rattlesnakes and snake-related art.

If drivers cross the rumble strip on this stretch of Route 66 at just the right speed it plays "America the Beautiful."

Eat like pre-Columbian Native Americans in this New Mexico restaurant within the Indian Pueblo Cultural Center.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

A journey begins with a single step, and for many, the road-trip of a lifetime started at this Chicago intersection.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

The US Navy's only submarine museum is also home to the world's first nuclear submarine.

Ruins of a historic medical facility sits eerily by the water.

New London, Connecticut still holds a grudge against its hometown son who turned traitor and burned the city.

Commemorating the spot where the famous scientist fed his pigeons.

This study room in the New York Public Library saw the creation of one of contemporary America's greatest traitors.