Hidden beneath the streets of London is a secret subway that only carried mail.

Started nearly 100 years ago, this science experiment just keeps on going, ever so slowly.

The convergence of two currents makes this a surprisingly pleasant getaway in the Arctic Circle.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

Visitors flock to see this church tower's unintended feature: It happens to resemble a giant chicken from multiple points of view.

Amid the sprawling Defense Intelligence Agency Headquarters is one of Washington's least accessible museums.

A magical work of architecture where a wind turbine enables monks to levitate.

An abandoned tank sits in an empty London lot as a symbolic middle finger to local city planners.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Elevated freight railway turned wildly successful urban park.

The famous facade of Grand Central Terminal hides a regulation tennis court, and it's not the first one.

The most confusing clock in New York.

Climb atop one of the world's longest and heaviest trains for an unbelievable journey across the Sahara Desert.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

This pseudo-steampunk weapons facility is the world's largest wood and glue structure, and packs quite a wallop.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

A museum dedicated to the alleged Roswell Incident.

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

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

Surreal riveted sea forts once protected the Kent shores from German attack.

Remember that scene in the Matrix, when Neo is in the big white room with all the weapons flying by? Well, this is what it would look like if he had wanted trees instead of guns.

The world's oldest continuously operating airport was founded by the Wright Brothers.