The striking jade death mask of an ancient Maya king is displayed in a replica tomb in Mexico City.

The ruins of the bathhouse used by the ill-fated last Aztec emperor still lie in Chapultepec Park.

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

This incredible college library is a visual masterpiece of mosaic art. It also looks kind of like a giant boombox.

This strange sculpture of a menacing skull surrounded by sun rays was discovered at the foot of the Pyramid of the Sun.

A museum in the former home of Marxist revolutionary Leon Trotsky.

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

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Part bookstore, part café, and part forest.

This palatial building has lived many lives as a convent, prison, cultural center, state archives, and government offices.

This cluttered cantina is famed for its cheese-spiked, raisin-flavored liqueur.

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

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

It was dubbed the "Garden of Plates" because it's covered in pieces of discarded dishes.

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

A hidden room within the church displays an amazing collection of old choir books.

The remains of a centuries-old water system that inspired local legends of secret tunnels.

This baroque wonder is filled with a trove of artistic treasures.

One man's personal collection of more than 2,000 creepy-crawlies from around the world.

The world's first museum of its kind is packed with nostalgic relics of the past.

This eerily opulent residential museum is home to a haunting local legend.

When struck, the strange stones in this park ring like bells.

The site of a fallen tree that protected Americans from British forces during the American Revolution.

This elaborate tunnel is the first structure composed of cast concrete in the United States.