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

The trials and tribulations of marking Poe's grave.

At 207 feet, one of the world's longest continuous escalators.

Every drop of D.C. tap water flows through this old waterworks.

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

The site of the climactic scene from the classic horror film is now a historic landmark.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

The most accurate timepiece in the world.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

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

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

The United States Capitol's former columns still stand.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

A museum dedicated to exhibiting remarkable outsider art.

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

This simple convenience store sits on the location where the Ouija board was named—and has a plaque to prove it.

Once America's tallest structure, now a Baltimore landmark.