A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

During Prohibition, the U.S. Congress had an "official" bootlegger, with his own Capitol Hill office.

The school tested mustard gas for the U.S. Army during World War I.

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

The early data processor factory founded in Washington for the 1890 U.S. Census went on to become IBM.

Before founding the American Red Cross, Clara Barton had a tremendous humanitarian impact by locating thousands of missing soldiers.

This unacceptably tall building was the real reason for Washington, D.C.'s skyscraper ban.

Before Nixon, "watergate" meant canals.

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

Home to a vast and influential collection of Shakespeareana.

There’s a special club house at the top for the bell ringers.

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

A much-maligned monument to teetotalism.

In the basement of the U.S. Capitol Building is a hidden storage room full of ornate floor tiles leftover from the 1850s.

Obscure Freemasons still live in D.C.’s largest private residence.

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.

This lovely pocket park is one of the most under appreciated in D.C.

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

Perhaps the most scandalous statue of America's first president.

The most accurate timepiece in the world.

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