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

The maritime museum that boasts the largest nautical library in the western hemisphere.

The resting place of a Civil War celebrity's amputated limb.

America's post-nuclear-attack chambers of Congress.

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.

The fastest transatlantic ocean liner sat abandoned in a Philadelphia shipyard for decades.

A museum dedicated to the strange and extravagant costumes and memorabilia of the mummers, a tradition older than Philadelphia itself.

An Irish Memorial commemorating those who perished due to potato blight.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

The first American department store, and home to the largest operating musical instrument in the world.

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

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Scattered throughout London are ancient remnants of the city's former bounding wall.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

An old saloon in the West filled with history, and according to some, a few dozen ghosts.

A wild west cemetery in Tombstone, Arizona, provides a window into the Old West.

A geological mystery on Camelback Mountain.

This haunted hotel built on natural springs once served as a hospital for a quack doctor promising a cure for cancer.

Where hills of dirt conceal the burial ground of one of the most powerful ancient Native American societies.

Final resting place of Geronimo, Quanah Parker, and the first atomic gun ever fired.

Sitting in the arguable birthplace of the Wild West, this museum holds the largest collection of bronco busting bric-a-brac in the world.

Like Mardi Gras, only everyone's a pirate.

This recently rediscovered Civil War-era submarine was the first to ever sink an enemy ship.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.