A domed disco abandoned since the '70s now attracts artists and explorers under its unique roof.

A massive cave complex boasts some of the clearest water (and most charming bats) in the world.

Rebuilt remains of a temple to Roman god Mithras.

This 700-year-old Cyprus castle is the birthplace of the world's oldest wine, said to be toasted by Richard the Lionheart at his wedding.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Hidden beneath the streets of London is a secret subway that only carried mail.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

A creepy sculpture of a decapitated head invites viewers to see St. Louis through its empty eyes.

A public urinal so pretty, it was declared a national monument.

This natural wonder is disappearing at an alarming rate.

Things aren't quite what they seem at this mind-bending museum.

Berry Gordy Jr.'s old home was the original headquarters of Motown Record Corporation.

A layered tribute to the work of mosaicist Isaiah Zagar.

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

An underground magnet for ever-changing street art.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

This modern antique shop is a museum for 1980's Saturday morning cartoon culture.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A museum dedicated to the history and exploration of both popular music and science fiction.

This Seattle joint serves food inside an old train car once used by FDR.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

Locals transformed this Canadian evergreen into a secret hangout with spectacular views of Vancouver's skyline.

A meow-velous tribute to a beloved street cat, made famous on the internet.