This nine-story building is the oldest standing skyscraper in D.C.

A portal into the bricked up canal that runs through the heart of Washington D.C.

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

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

Go take a picture with the inventor of the daguerreotype photographic process.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

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

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

Seemingly unremarkable items like empty sushi trays, chef hats, and freshness stickers are being preserved so future generations can look back on this beloved cultural import.

The most accurate timepiece in the world.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

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

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

This former asylum for Black Americans is haunted by its history of violence and racism.

Once on display alongside a giant Gumby, it’s as tall as a nine-story building when fully extended.

Inspired by a foil-wrapped potato, (seriously) the Markel Building has been deemed one of the 10 ugliest buildings in the world.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

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

The celebrated eyesore created by starry-eyed sweethearts.

Peek through the gates at this oasis from the city, full of Old English charm.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This symbolic piece of New Orleans architecture is also home to a few ghastly stories.