The curios of pharmacist and collector Henry Wellcome.

At night, bats patrol this magnificent 18th-century space in search of book-eating pests.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

A once-secret library of Freemason history in Catalonia.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

This shop for all your super spy needs hides an educational secret.

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

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

Astounding collection of coin-operated games and automata.

The only surviving prototype for Buckminster Fuller's house of the future.

The Beaux-Arts aquarium boasts a vast collection of saltwater and freshwater fish on an island in the Detroit River.

Over a thousand feet beneath the Detroit streets is a subterranean metropolis few are allowed to enter.

Detroit housing collective working to create an "environment for revolutionary change."

This public baseball field is a beloved remainder from of one of the most historic stadiums in the country.

This historic Jewish cemetery sits right in the heart of a Detroit car factory.

Glass and concrete building designed by Albert Kahn.

To truly appreciate Detroit's landmark skyscraper, you have to step inside.

The collection of ceremonial and cultural objects spans many countries and hundreds of years.

The world’s largest Masonic temple was saved by the White Stripes.

A Beaux-Arts triumph set to become Ford's innovation campus

The bones of an old zoo crumbling in the shadow of a new one.

Destructive children, start your engines.

This "Plant Farm Museum" is home to the divinely inspired and visionary outsider artwork of Reverend Howard Finster.