The hallucinogenic center of the ancient world.

A mysterious castle built as a monument to lost love.

A building so large that it has its own weather.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Ordinary art transforms to extraordinary thanks to locals' quirky sense of humor.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

France's most famous cemetery, with some of its most curious tombs.

Pilgrimage site for star-crossed lovers.

An incredible mosaic-lined monument said to have held the remains of an ancient Roman empress.

A medieval, mosaic-lined baptistry built by a heretical Christian sect.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

Psychoanalyst Carl Jung reported a paranormal experience after visiting this mosaic-lined Roman baptistry.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

The roof of this ancient mausoleum is made from a single Istrian stone weighing a massive 230 tons.

This natural gas vent certainly earns its name as the smallest volcano in Italy.

Famous landmarks and structures from across Italy fill this miniature park.

One Italian taxi driver covered his entire house in small seashells creating a weird bit of architecture that is preserved to this day.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

Romans built the world's tallest artificial waterfall in 271 BC.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Copenhagen's celebrated theme park and gardens.