A beautiful example of 18th-century engineering still standing tall.

This historic Mexican convent is home to a tree that grows crucifix-like thorns.

On a picturesque lake island, a massive, “broken” crucifixion has become a popular pilgrimage destination.

This grand yet little-visited tomb seems almost carved into the hill it sits on.

The extremely grey columns of one of Mexico City's most iconic beltways are slowly gaining a bit of color.

The spectacular subterranean collection includes dazzling minerals, including a piece of "kryptonite."

From Nunavut to Tierra del Fuego, you won't find any lighthouse higher than this one.

Iconic red and white plaques show the creative names invented to navigate the city streets.

Hotel designed around a 16th century Mexican bullring.

The first public library in the Americas has more than 45,000 books dating back to the 15th century.

Come face to face with the ferocious visage of the serpent-headed mother goddess of the Aztecs.

Mexico's largest collection of masks is found in the ruins of an abandoned convent.

Once home to an aristocratic family and a workers' organization, this intricately tiled building now houses a chain restaurant.

On a cornerstone of the City Museum is the head of a monstrous serpent stolen from an Aztec pyramid 400 years ago.

Inside this mountain lies several kilometers of breathtaking caves.

This foreboding building was the headquarters of the terrifying Spanish Inquisition in Mexico.

A Lovecraftian altar of nightmarish bronze chairs sits ominously on a boardwalk in Puerto Vallarta.

Many people don't realize there’s a lot going on in—and below—the world’s tallest triumphal arch.

A 500-year-old series of tunnels long believed to be folkloric was uncovered beneath the streets of Puebla.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

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

Gilded heaven for philatelists and architecture freaks, still in full working order despite sitting atop tremulous ground.

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

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