This lush forest valley was once mined for lumber to the extent that it was once nicknamed "The Pennsylvania Desert."

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

Over 100 concrete munitions bunkers are all that remain of a Pennsylvanian village seized by the US government.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

Huge masonic hall in Philadelphia with lavishly themed rooms.

This hospital fell into ruins after failing to act as the advocate for the mentally ill it was designed to be.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

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

Art deco landmark on the outskirts of Washington, D.C.

A brass plaque dedicated to a convicted cannibal hangs in the National Press Club, and that's not even the craziest part of the story.

The national park was once a plantation estate.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

A double agent hid information for the Soviet Union beneath this bridge for more than 20 years.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

This grand gothic brewery has been pumping out suds for over a hundred years.

A small triangle of DC grass is the final resting place of one of Sonny and Cher's songs.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

‘Bush the old fire dog died of poison July 5th, 1869. RIP.’

An Industrial Revolution-era public work that purified water using nothing but sand.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.