Art Deco stylings conceal the true nature of this bridge.

A replica of the first public theater built in California.

Four hundred granite steps were built into this massive rock by the National Park Service.

A 19th-century cabin built into a hollowed-out Sequoia tree.

A glimpse into the lives of the the Miwok and Paiute people in Yosemite National Park.

The interior of the Overlook Hotel in "The Shining" was based on this Yosemite original.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

Oldest building in California still in use.

Colorful Native American paintings are hidden within this small cavern.

Hidden in the Santa Ynez Mountains off Highway 154, this tiny restaurant once served as a stagecoach stop.

This stunning sea creature-shaped home blends into the landscape like a fantasy villa.

Pillars made of 700 pieces of luggage climb to the ceiling of Sacramento Airport's baggage claim.

A massive volcanic plug is now a protected area that hosts a number of bird species.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

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

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

There’s a hidden military meme engraved on the World War II Memorial.

A historic arena where the Beatles played their first concert in the U.S.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

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.

The house where John Wilkes Booth conspired with his co-conspirators.

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