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This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

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

The headquarters of the Fraternitas Rosae Crucis, complete with Rosicrucian pyramids, all in the Pennsylvania woods.

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

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

Huge masonic hall in Philadelphia with lavishly themed rooms.

In which a local geological marvel becomes a quaint roadside attraction.

A park full of outsider art, created by college students studying outsider art.

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Mural made of 100,000 pieces of hand blown glass, and one of the largest glass murals in the US.

Mysterious rocks that ring musically when struck.

A layered tribute to the work of mosaicist Isaiah Zagar.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

The taxidermied remains of Charles Dickens' pet raven, which helped inspire one of Edgar Allan Poe's most famous poems.