A derelict bit of transportation infrastructure hidden in the woods.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

The school tested mustard gas for the U.S. Army during World War I.

This North Carolina store preserves a historic moment in America's movement for racial equality.

The most accurate timepiece in the world.

A plaque outside the San Jose airport commemorates the insect's arrival to the West Coast.

Ancient serpentine sacrifice holder that has stood the test of time.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

A fountain standing as a testament to a doomed alliance.

A marvel of Byzantine engineering under the streets of Istanbul.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

Legend says if you stick your thumb in the hole and it gets wet, your wish will be granted.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

Former utopian colony based on the belief that the universe exists in a hollow sphere.

Wading through a small lagoon reveals a secret, wild stretch of pristine beach.

A hidden beach at the end of a tunnel of mangrove trees.

An abandoned vacation home spent a decade taking on legends. It's now taking on water.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Washington's iconic carousel has a nice piece of Civil Rights history.

This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

Every December the Wannalancit Mills lights a Christmas Tree over the old mill's smokestack.

This classic red schoolhouse is said to have been where Mary and her little lamb went to school.