This massive swimming pool is the high tech home to the human-powered submarine races.

Home of the physician who set the leg of John Wilkes Booth after the Lincoln assassination.

The world's oldest continuously operating airport was founded by the Wright Brothers.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

Two dozen pinball games hidden away inside a most unlikely location.

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

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

This English-inspired Maryland garden is home to acres of opulent plant life including bushes shaped into an entire fox hunt.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

The trials and tribulations of marking Poe’s grave.

An astounding collection of medical specimens, including bits of President Lincoln.

A museum dedicated to exhibiting remarkable outsider art.

There must be a pun in this haystack somewhere...

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Cryptic messages embedded in the New York City sidewalk.

A bit of retro transportation flair preserved in the world's largest department store.

Elevated freight railway turned wildly successful urban park.

A millionaire's abandoned swimming pool from the gilded age of one of America's most distinguished families.

Whale bones, scrimshaw, and sperm oil make up just a part of this comprehensive collection of whaling history.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

This little replica of Lady Liberty provides a bit of NYC in a Japanese city.

After a profound show of devotion for his master, a dog becomes the symbol of loyalty for an entire nation.

A 20-meter (65-foot) robot towers over Tokyo Bay.

The world’s first penitentiary, meant to be humane, drove men insane.