Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

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

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

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

Look closely and you’ll notice that the color changes a third of the way up the tower.

Washington's iconic carousel has a nice piece of Civil Rights history.

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

The national park was once a plantation estate.

There’s a hidden military meme engraved on the World War II Memorial.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

People escaping slavery may have hidden inside a corpse vault.

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

A secret rendezvous spot where John S. Mosby and his Rangers would meet to divvy up their loot after raids.

These unusual rooms on wheels are holdovers from the 1960s.

Built in the 1850s, this church was of the first five churches constructed in Harper's Ferry.

This shale formation along the Appalachian Trail once inspired the third president of the United States.

This advertisement for talcum powder was painted on the rock face and has since defied removal.

This unattributed sculpture in Amsterdam is hiding in plain sight.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Cat art as far as the eye can see.

A floating cat sanctuary on an Amsterdam canal.

A preserved building where the dead were once watched for signs of life.

The largest 19th century panorama in the world still in-situ.

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