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

Decades before the scandal, this staircase on the river was a literal "water gate."

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

An abandoned church gets a second life as a massive beer hall and event space.

An eerie, abandoned military base engulfed by nature and graffiti is now home to a local park.

A hidden alley in urban Baltimore is a haven for graffiti artists.

This beloved Baltimore spot features caged dolls, a giant Pez collection, and many, many mannequins.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."

At this former Prohibition speakeasy, electric birds signaled the arrival of hooch.

Alexander Hamilton’s creation caused quite a bit of controversy.

South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

This Philly landmark has a giant butterfly pavilion, three floors of insect displays, and withstood a $40,000 heist.

This elaborate towering structure was once famed for its revolutionary height.

The abandoned coal loading dock is a canvas for unsanctioned art.

Enjoy a slice while browsing the world's largest collection of pizza memorabilia.

Huge masonic hall in Philadelphia with lavishly themed rooms.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

A rare view of a preserved Victorian science museum.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

A layered tribute to the work of mosaicist Isaiah Zagar.

World's first "penitentiary," meant to be humane, drove men insane.

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