A haunting tribute to pioneering photographer Clover Adams.

This covered bridge was used by both Union and Confederate troops during the Battle of Gettysburg in 1863.

This twice-relocated "Usonian" home is among the smallest built by master architect Frank Lloyd Wright.

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

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

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

This bridge over D.C.'s Rock Creek Park is sometimes called the "Buffalo Bridge" because of its four buffalo sculptures, which were cast from a single piece of bronze.

The national park was once a plantation estate.

Live data is transmitted from the Atlantic coast to instantly recreate the ocean waves in this fountain at the NOAA headquarters.

This Art Deco service station has been providing tune-ups and turning heads for close to a century.

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

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

Press 1 for knock-knock jokes.

The last of nine massive kilns that produced many of the red bricks for buildings in Washington, D.C. and northern Virginia in the early 20th century.

Built in the 1970s, this curious modular home found new life as a sundae-shaped ice cream stand.

These massive concrete balls were used to mine gold in Virginia.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

First built around 1848, this bridge was destroyed by arson, but original timbers are included in the replacement.

This one-room cabin where the young colonel slept during the French and Indian War.

Washed out by the Johnstown Flood in 1889, the surviving portion of the original two-span bridge now resides at Fishing Creek.

The ruined remains of a coal mining ghost town are hidden within the woods.

Memorializing an American tragedy of massive proportions.

A decidedly out of place statue memorializes the Blues Brothers characters at this water bottling plant.

The house and graveyard used in the Stephen King spine-chiller.