The bookstore with bookshelves built into unlikely places.

The crypts are so large they're basically their own underground church.

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

The underground mall's skylights look like they could be part of a spaceship.

The unique collection of gifts includes braids of human hair, a spoon, and a Virgin made of bread.

The unique collection often goes unnoticed by visitors focused only on the archaeological objects.

Inside a busy metro station, an impressive mural depicts the prehispanic city of Tenochtitlán.

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

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

These haunting ruins of a 700-year-old Prehispanic city have witnessed centuries of wars and massacres.

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

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

The famous artist couple lived and worked here, in two different houses separated by a bridge.

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

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

An antiquated German apothecary on Chicago's North Side.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

Illegal drag racing two stories beneath Chicago’s streets.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

This easily overlooked memorial immortalizes the scars from the 1956 Hungarian Revolution.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

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

A monument to the man who almost killed Hitler.