A self-proclaimed libertarian micro-state on a tiny bit of disputed territory between Serbia and Croatia.

This beautiful eden was once the vacation home of Tahitian royals before Marlon Brando bought it.

Back in the tiny USSR.

Dr. Strangelove-esque tours reveal the inside a bunker once reserved for Stalin himself.

Geometry and mystery come together in an epic show of octagonal masonry.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A naturally beautiful, seemingly bottomless deep blue spring.

Southern Italy's spinning top village.

An ethereal glowing blue ocean cave in Croatia.

Small on the outside, big on the inside, this church is an astonishing act of visual deception.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

A curious cave church carved into the face of a cliff.

A hand-built folk art installation covered with messages of God's love.

An old vending machine serves up unpredictable beverages from its seemingly magical insides.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

An exquisite tunnel of cascading flowers.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A massive underwater sinkhole made famous by Jacques Cousteau.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.