A mysterious echo seems to defy the laws of acoustics.

This once-grand marvel of engineering is now 41 miles of scenic hiking trail.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

Haunted Victorian house that inspired a legendary "Ghostbusters" court ruling.

The home of one of America's most wealthy industrialists is now a historic site that remembers a more decadent time in the country's history.

Oldest existing church in New York and the inspiration for Washington Irving's "The Legend of Sleepy Hollow."

A beautifully designed asylum was resurrected as a hotel and art center with a ghost story or two.

For over 80 years, Mayan ruins stood proudly in a most unlikely location.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

The Hudson River School comes alive at this palatial estate.

The abandoned ruins of America's first private zoo are open for exploration in the Catskills.

A 10-foot-tall concrete Alley Oop statue left over from World War II now stands on the side of the road.

Surprisingly aquamarine waters fill deep lakes formed at the end of the last ice age.

Possibly the smallest church in the world floats in the middle of a pond.

Three acres of mythology-inspired sculptures are visible from the highway.

The first American home of the isolated, egalitarian religion has a trove of Shaker architecture and artifacts.

The floor-to-ceiling collection in an old factory is a unique alternative to stuffy galleries.

A beautiful final resting place with some surprising residents.

"Call for the doctor, call for the nurse... Vote!! said the lady with the alligator purse."

The Fox Sisters, America's leading mediums in the mid-19th century, possessed a table they claimed helped them "communicate" with the dead.

An old dining hall now serves up ghost stories for lusty locals.

Comprehensive gaming collection of over 30,000 electronic games and consoles.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.