A natural sandstone bridge hidden in the Sewanee forest.

More than five miles of underground passageways.

Incredible miniature towns and buildings created and decorated with thousands of tiny rocks.

Bad farming practices caused this unnatural natural wonder.

The 320-year-old tree that greeted General Lafayette and rerouted an interstate highway.

One of the oldest anatomical theaters in the U.S. still in use was once the site of an infamous cadaver riot.

A curious whirlpool formation supposedly capable of entangling or engulfing branches, tree trunks, or whole rafts full of hapless tourists.

Inside this old train depot resides a multi-line model train covering western North Carolina.

A 315-foot spire jutting out from the Blue Ridge Mountains makes for breathtaking views.

Replica of an old Esso filling station, complete with Wayne gravity pump and outhouse.

A park where you can watch the highway zoom past.

Finale of "William Tell Overture" can be heard as drivers pass over grooves in the road.

The road plays 30 seconds of the Marine’s Hymn when driving over the grooved pavement.

An extraordinary natural landscape of mountains, waterfalls, and rocky cliffs riddled with tunnels.

The remains of a British railway rusting in the jungle mist of a Brazilian mountainside.

An abandoned stretch of elevated road in the middle of the Brazilian jungle.

A 30-foot-tall goat tower in central Illinois is home to a herd of Swiss ungulates.

Step inside Lucy, the world's largest "elephant."

The last of Philadelphia's wood-paved streets is now a landmark of terrible engineering.

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

A tragic mystery left this boy nameless for 65 years.

Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

Ant sculptures march up the side of what used to be an iconic spot in punk rock lore.

The abandoned coal loading dock is a canvas for unsanctioned art.