Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

A relic of FDR's brief foray into utopian urban planning.

Remnants of a storybook amusement park hidden behind a strip mall.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

The oldest continuously operating fish market in the United States.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

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

The United States Capitol's former columns still stand.

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

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

Like Mardi Gras, only everyone's a pirate.

The land is home to swimming ponies and a legendary 18th-century treasure.

Bizarre Cavern.

Meet manatees face-to-face at this zoo for native species.

A vast array of tropical plants collected by a vacationing couple.

A haunted hill that supposedly defied gravity.

The only runway directly into the magic kingdom has been closed since 1972, but it still sings to you if you drive fast enough.

Electrical pylon in the shape of Disney's beloved mouse.

After the attack on Pearl Harbor, rocks and fossils from every U.S. state were collected into a pyramid of national unity.