Sacred Indian temple that’s all monkey business.

One of the most horrible legacies of the Cold War is a site where the Soviet Union tested nuclear bombs on civilians.

There's a crumbling old mansion inside the Smithsonian National Zoo.

Filled with history, this cemetery is maintained each summer by a few hungry goats.

Hidden inside one of the world's most well-visited zoos is a secret plaque promising eternal life.

This foolish Victorian sea fort was converted to a deluxe hotel.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

One of New Jersey's oldest churches is a historical treasure trove.

A replica of the famous memorial statue at the Normandy American Cemetery hides in an office building in downtown D.C.

The 28,000-year-old specimen is remarkably intact.

This unassuming passageway played a key role in one of the most important events in U.S. history.

When it comes to handsignals (and colonialism) rock always beats scissors.

Washington's iconic carousel has a nice piece of Civil Rights history.

A historic ruin just 20 feet away from a busy highway onramp.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

A haunting tribute to pioneering photographer Clover Adams.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

A Spiritualist house of worship where believers communicate with the dead in the spirit world.

A derelict bit of transportation infrastructure hidden in the woods.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

A painfully obvious spy house sits right across the street from the Russian Embassy.

It was once the base for a series of domestic terror attacks.

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

These abandoned waterworks are crumbling into the Potomac River.