A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This bridge was constructed from the rubble of the infamous Bastille.

Scattered throughout London are ancient remnants of the city's former bounding wall.

This one has sailed five times as far as Sir Francis Drake's famous ship.

Famously misunderstood wonder of the ancient world

Go inside to really appreciate this 500-year-old technological masterpiece.

100 year tradition of fist fights, marked by marble footsteps.

Macabre astrological automaton clock dating to the late 1400s.

A saintly relic hidden in a Prague church basement.

Cold war icon and onetime "hole" in the iron curtain.

Come for the flowers, stay for the bats!

The Victoria-era quarantine station for Sydney.

Granite rocks that concentrate waves into powerful jets.

Rainforest filled with record-holding eucalyptus.

The once-dying town of Sheffield, Tasmania has reinvented itself as a village of painted wonders.

One of the best beaches in the entire world.

This extraordinary geological oddity resembles human-made pavement.

Relics of Australia's convict past, and a modern scene of unimaginable horror.