These enigmatic ruins continue to vex archaeologists.

A natural swimming hole that was once a ceremonial center for Mayan priests.

This staircase in a lush tropical grotto was built by enslaved laborers and renamed to honor Queen Victoria's role in ending slavery in the British Empire.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

The yawning maw of this pagan visage is said to bite off the hands of liars.

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

Two stone columns flank the grand Venice square, but there were supposed to be three.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

The stones of this formerly witch-obsessed castle were used to build a church.

An abandoned train station in Munich constructed for the 1972 Olympic games.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

This German fountain of a legendary apple wine-loving drink thief will spit on you.

Carved fountains poignantly placed in parks and in front of special monuments.

A German apartment building hosting as many trees as human occupants.

Crop circles inspired this whimsical garden in Germany.

The zoological collection at the Hessisches Landesmuseum hosts some of the world's oldest habitat dioramas.

A former Nazi lookout tower with a magnificent view of the Rhineland.

This natural "sea of stones" was once used by the Romans as a quarry.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

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

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

This historic toy museum brings a little whimsy to a city not usually remembered for such things.

This lurid German fountain plots the sad course of marriage from dating to death.