Before Nixon, "watergate" meant canals.

The national park was once a plantation estate.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

An engineering marvel at the time of its construction, this cross-border waterway sought to connect the Black Sea to the Baltic.

Tucked away along a riverbend in an area known for its uranium mines is one of the world's tallest locks.

Hiding behind a grocery store is a spectacular cavern carved as part of an old limestone quarry.

Many people don't realize there’s a lot going on in—and below—the world’s tallest triumphal arch.

The "Bridge Over the Atlantic" lets you cross the waterway in mere seconds.

A bronze bust commemorates the heroism of the secret agents who led covert operations against the Nazis.

Its appearance in "Game of Thrones" may spur on the long-awaited restoration of this medieval shipyard.

This unique temple complex remains off the typical tourist trail.

An abandoned 17th-century baroque hunting lodge with a wonderfully strange architectural plan.

A powerful cyclone once made one of the world's largest sinkholes completely fill with water.

Some claim these desert ruins are from the legendary "Atlantis of the Sands."

These gnarly desert trees produce the prized aromatic resin traded along the ancient incense trail.

A clerical error gave rise to this imaginary micronation in the southwestern corner of Estonia.

Where artisans use centuries-old techniques to build traditional Arabian ships.

This lonely tomb is all that remains of a once-bustling ancient trade hub visited by Marco Polo.

This natural wonderland is a unique chance to explore a Carolina bay, a mysterious geological formation of unknown origin.

Moonbows over Kentucky.

This Florida sinkhole hides a rainforest-like micro-environment in its depths.

At this Minnesota state park you can easily wade across the source of the mighty Mississippi.

The eerie ruins of a remote abandoned hamlet said to be founded by the survivors of a shipwreck.

Mysterious Incan ruins on a tiny island in Lake Titicaca.