A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

A brush maker used his factory to protect blind Jews from the Gestapo.

These former Nazi anti-aircraft towers offer a singular view of the north of Berlin in the summer, and a sanctuary for bats in winter.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

An astonishingly accurate water clock that doubles as an hourly spectacle in this Berlin shopping area.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

The world's first clock to use set theory as a measure of time required the invention of a new light bulb just to maintain its obtuse measurements.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

The same water that fills a luxury resort’s pools feeds these free hot springs in the rainforest.

This wildlife refuge is home to more than 200 species of birds, as well as monkeys, lizards, and other wildlife.

Along a coast that sees the annual migration of humpback whales, a geological formation that takes the shape of a whale’s tail.

Pop culture has helped to keep this iconic British building from being destroyed.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

Sculptor Antony Gormley used chaos theory and fractal growth to design his tallest creation.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

The sculpture of the deceased cockatoo flops atop its personal plinth.

Giant, friendly pelicans in Central London, the most unlikely of places.

The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

Hear the quietest sound from across the dome.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.