The first curved wooden bridge in Canada was built as part of the Alaska-Canada Highway.

Home to a full cast of the largest woolly mammoth ever recovered in North America. 

Roadside collection of 65,000 signs.

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

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

An unconventional monument to one of America's largest landowners.

A saloon and inn that served the Wild West's most iconic figures—and is still haunted by some of them today.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

The only Leonardo Da Vinci painting in the Western Hemisphere.

Railroad officials in the early 1900s sought to spare travelers the sight of Roman soldiers’ private parts.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

The tunnel under the Capitol Building where Congress takes out its trash.

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.

This statue of the "father of television" stands prominently in the United States Capitol.

This statue of one of baseball’s greatest pitchers looks like something out of a sci-fi horror movie.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

The National Park Service’s best-kept secret with views that rival any in D.C.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

An overlooked memorial honoring the local Washington residents who died in World War I.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.