The most powerful waterfall in all of Europe.

A quiet memorial to those who died saving others in the heart of the City of London.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

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

A picture-perfect town, perfect for blowing up.

Where the leftovers of love affairs can live on forever.

The 1936 Summer Olympics site is a crumbling remnant of sportsmanship and a history its host country would like to forget.

One woman's dream became a train hotel in her backyard.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

Step into the cool deep past and unknown future of who begat who.

Largest collection of mounted dinosaur specimens in the world.

The largest island on the great salt lake is home to curious creatures and strange stories.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Mexico City's residents are being watched by this state surveillance headquarters, designed by architects with a flair for intimidation.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

Home to secret Eastern Bloc spy equipment and the largest stretch of the original Berlin Wall outside of Germany.

The other side is actually green.

This magnificent blue mosque in Afghanistan is surrounded by thousands of white doves.

Planned as the world’s first zero-carbon city, it had lofty ideals—but is only 5 percent completed and aiming for 50 percent carbon-neutral.

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

One of the deepest indoor swimming pools in the world.

"You don't need a rocket scientist to build a steam engine, but we've got one." -Museum docent on the credentials of a restoration volunteer.

Narrow-gauge railway with its own personal power grid.

The prototype for all Nazi concentration camps.