The world's largest drain sits below the city of Kasukabe, Japan.

Once the most densely populated place in the world, this island is now a ghost town.

The second largest maple syrup producer in the U.S. runs a high-tech operation.

A famed data visualizer's personal sculpture garden is a landscape of modern and megalithic wonders.

The final resting place of the world's first nuclear reactor.

A park in Mexico offers all the experiences of an illegal border crossing except for one: the border.

There’s a hidden military meme engraved on the World War II Memorial.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

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

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

The wreckage of a World War II bomber is hidden high in the Colorado wilderness.

The shortest river in America flows for just 201 feet.

This top secret Chinese military megaproject is the world’s largest human-made tunnel structure.

If drivers cross the rumble strip on this stretch of Route 66 at just the right speed it plays "America the Beautiful."

Deadly airliner crash preserved for those willing to climb and pay respects.

This historical air terminal in Houston is slowly becoming an aviation museum dedicated to the city's aeronautical history.

Every weekend, people gather here for a brief chance to see their loved ones on the other side of the United States–Mexico border.

The stone circle honors the 19 firemen who perished during the Yarnell Hill Fire.

The first permanent memorial to a unique secret weapon of World War II.

Concrete crosses scattered across the Arizona scrubland which were used to align spy satellites.

Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

Modern technology and live displays tell the story of the Pacific during WWII for the Internet generation.

This unassuming layer of clay boasts an out-of-this-world origin story.

A unique museum where guests can rent and operate a locomotive.