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

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

An overlooked memorial honoring the local Washington residents who died in World War I.

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

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

The most decorated dog of World War I is preserved in the Smithsonian.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

A grotesque Fiji merman dwells within this traditional Dutch-style building.

The historic home still shows the scars from a little run-in with the British in 1813.

The world's largest rotating world.

The sweetest graveyard in the world is filled with headstones for dearly de-pinted ice cream flavors.

Come for the gun-toting hillbilly madman, stay for the ice-cream loving basketball bears.

Even Henry David Thoreau found this glacial pothole irresistible.

According to the experts at the Guinness World's Record office, this is the longest candy counter in the world.

A serene plaza that commemorates one of the Granite State's most iconic figures.

The highest point in the state of New Hampshire, and while unlikely "the worst weather in the world," it sure seems that way to hikers.

The 100-year-old public collection of a New Hampshire dentist that contains taxidermy, Native American artifacts, and a pair of mummy hands.

The dress young Pierce wore prior to his breeching ceremony in the early 1800s is now on display for all to see.

Carved, egg-shaped stone with no explanation.

Scene of the grisly murder of two Norwegian women in 1873.

The only one of New Hampshire's original 14 World War II watchtowers to survive in near-original condition.

The once-abandoned 140-year-old hotel used in the movie "In Dreams."