Even Henry David Thoreau found this glacial pothole irresistible.

The eccentric mansion of one the most popular horror authors of modern times.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

This elaborate towering structure was once famed for its revolutionary height.

World's first "penitentiary," meant to be humane, drove men insane.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

The trials and tribulations of marking Poe's grave.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

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

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

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

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

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

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

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

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

Giftshop catering to cryptozoologists and anyone with a sense of humor.

A small triangle of DC grass is the final resting place of one of Sonny and Cher's songs.

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

A Borgesian work of art that may blur the line between fiction and reality a little too convincingly.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

Home to the Amorphophallus titanum "Corpse Flower," which is among the largest flowers in the world and also smells powerfully of rotting flesh when in bloom.