The only castle in North America to ever house European sovereigns.

The splendor of this 17th century golden chapel has led it to be called the "eighth wonder of the world."

The winter home of millions of migrating monarch butterflies.

Mexico's astounding mummy museum with "the world's smallest mummy."

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

66,000 pieces of art, donated by one of the world's richest men.

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

High atop a Mexican rainforest mountain, this ancient pyramid once drew pilgrims countries away.

Part bookstore, part café, and part forest.

Frida Kahlo's childhood home, now a museum of her life and works.

Superstitious? Discover the witchy side of Mexico through its largest esoteric market.

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.

A fairy garden in an old hotel hidden in La Marquesa forest.

This strange building looks like a medieval fortress crashed into a 1960s Brutalist office block.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

At the very tippity-top of Europe is a cliff from which you can view the midnight sun.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

Golden cobblestones remember a time when this small alley was used to avoid having to give a Nazi salute.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

Among the ostentatious rococo ornamentation of this church, an image of death cuts the life-thread.

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

A church filled with the bones of hundreds of virgins martyrs—or so they say.

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