Eccentric concrete mansion and museum designed and built by hand from the inside out.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

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

A rare view of a preserved Victorian science museum.

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

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

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

A local farm's collection of unusual structures from a now defunct storybook amusement park.

The oldest surviving botanic garden in the United States.

Ship skeletons haunt Baltimore's waterways.

Descendants of this colonial Pennsylvania family still travel from far and wide to visit the 300-year-old home of their Quaker ancestors.

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

This free, take-a-book shop seems like a trick but isn't.

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

The home and studio of a visionary woodworker now stands as a museum and example of his artistic genius.

This one-room cabin where the young colonel slept during the French and Indian War.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

Endless rows of boxes of paper records line the hallways of the archaic federal facility where guns are traced.

An eerie, decaying ghost town destined to fade into the forest.

The internal railway of one of the biggest steel plants in America has been transformed into a linear park with unique industrial views.

It would take 35 firetrucks to fill this enormous glacial pothole.

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

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

A modern ghost town whose inhabitants were driven away by the growth of nuclear power.