Mexico City's largest market contains a Willy Wonka-esque wonderland.

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

These biodiverse university gardens form a green oasis amid the urban chaos of Mexico City.

Explore the atmospheric ruins of an abandoned convent in the dense forests of Mexico's first national park.

A disquieting Aztec sculpture displays hundreds of stone skulls representing the victims of human sacrifice.

This crumbling Art Deco movie palace in Mexico City has been abandoned for two decades.

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

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

Diego Rivera's massive tiled fountain and failed infrastructure project.

Visiting this cacophonous collection of vintage novelties is like stepping into the mind of a crazed toymaker.

Part bookstore, part café, and part forest.

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

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

An island filled with hundreds of hanging, decomposing, decapitated dolls.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

A terrific purveyor of natural history objects and curios.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

Small and slightly hidden, the American Writers Museum is preserving the legacy of America's finest authors.

This awkward aquarium sculpture is one of the strangest statues in Chicago.

To find the "unicorns of the deep" you've got to go downstairs.

A curious collection of miniatures in a quiet corner of the Chicago Children's Museum.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

A hot dog stand where the heads are just as hot as the dogs.

At Chicago's revered Field Museum, visitors are invited to learn about and literally explore DNA.