Yugoslavia's biggest underground airport lies in ruins.

Nightmarish example of the unintended consequences of weapons testing.

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

The haunting ruins of Jack London's dream house.

An electrifying collection of gadgets and literature from the 16th through 20th centuries.

This expansive bridge in the Canadian wilderness was originally just built for friends.

The mountaintop wind turbine boasts a viewing deck — and a fair share of controversy.

From mining complex to industrial exhibition, this museum once played a major part in the X-Files.

The century-old plant starred as the villainous clown's lair in the miniseries based on Stephen King's "It."

Railways may have forged this quintet of lovely tunnels, but now they are open to hikers.

With a floor made of thick glass, this observation deck offers a full view of Sunwapta Valley's mountains and rivers.

For decades these polar bears have roamed all around a Nashville neighborhood.

The alley connecting two of country music’s most historic venues has a rich history of its own.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.

Visit this playground of waterfalls, caves and sinkholes.

This circus town museum recognizes the outstanding clowns of history.

Hidden away in the city of Madison, Wisconsin is a nearly forgotten home that Frank Lloyd Wright built for a childhood friend.

One man's ambition created this psychedelic log home.

Extremely long cable tunnel buried under the river.

A statue of the early navigator stands overlooking the land he first surveyed.

A beautiful waterfall and beach where precious stones are plentiful.

Ice roads, deep holes and 3,500 pounds of diamonds.

Built after the 1991 discovery of one of the world's most complete T.rex skeletons in the nearby hills.