The largest earthwork effigy in the world.

A slab of sandstone covered with mysterious 1,000-year-old rock carvings from a vanished North American culture.

This national landmark is also home to a massive treehouse.

A monument to an Irish secret society thought to be responsible for a string of violent attacks in Pennsylvania coal mines.

Outside a small brewery, a Gothic fountain that once provided water to thirsty horses.

The only geyser in the state of Pennsylvania is caused by pressure from an abandoned coal mine outside of the ghost town Centralia.

A eight-foot-tall statue resides in the heart of Pennsylvania anthracite coal country.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

A toxic ghost town sitting atop a massive coal fire.

An underground blaze turned this village into a ghost town.

Over 100 concrete munitions bunkers are all that remain of a Pennsylvanian village seized by the US government.

A retired firefighter created this contraption so he and his family wouldn't die if accidentally buried alive.

According to local myth this cemetery is half evil spirits, half good—split down the middle.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

This unique creation was made by the largest manufacturer of Christmas bulbs in 1946 to honor those returning from World War II.

All that remains of one of the Civil War's more deadly POW camps is a simple flagstone.

The wooden octagon in which Huckleberry Finn and A Connecticut Yankee were born can still be visited in upstate New York.

This formerly abandoned amusement park includes a classic carousel and a replica of Mark Twain's famous hut-like Elmira study.

A historical home in upstate New York honors the work of John W. Jones, a formerly enslaved man who was a major agent for the Underground Railroad.

The little-known final resting place of one of America's greatest writers.

A dozen U.S. presidents have stayed at the historic resort, which was known as James Buchanan’s “Summer White House” from 1857-1861.

This Art Deco service station has been providing tune-ups and turning heads for close to a century.

Overshadowed by quilts, the artistry of these patterned textiles went underappreciated for too long.