An ancient irrigation system that turned arid deserts into oases.

God's Saharan sandbox of wrath.

Huge concrete structures designed as an early warning system for Britain to detect enemy aircraft.

See the lake and replica where a daredevil broke both world land and water speed records in the same year.

A geothermal paradise with bubbling mud pools and bright blue hot springs.

A tiny village church in dramatic surroundings.

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

Europe's "only museum dedicated to the decapod" is full of quirky and absurdist displays, including one featuring the "famous" Giant Crab of Margate.

A defensive structure built during the Hundred Years War has remained useful in one way or another for nearly 700 years.

Inspired by Thomas Stothard's painting of the "Journey to Canterbury," albeit with Canterbury natives.

This skewed English house has looked like it's going to fall over for centuries.

A black sand beach where glacial fragments wash ashore and look like sparkling diamonds.

Amidst medieval and baroque buildings, five human-sized gherkins stand tall.

The beautiful, ornate weather station is the most popular geocache in Salzburg.

This small Bavarian graveyard is filled with empty graves for German soldiers lost during the World Wars.

This underpass became an unlikely piece of cinematic history after its appearance in 'A Clockwork Orange.'

Grotto replete with mystical designs laid out in glued shell mosaics.

Overlooking the seaside town of Margate stands a tribute to an artist's lover.

Henry VIII's forgotten castle was built by the gunpowder-obsessed king to be defended solely by cannons.

A unique bridge with an equally unique view.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

This strange sculpture depicts a giant nightmare hare crushing a man to death beneath its colossal bulk.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

A collection of 20th-century automata, penny arcade games, and musical contraptions.