An autonomous republic of Orthodox monks.

Op-art architecture designed for happiness.

This cubist Vienna church building looks like some sort of alien stonehenge.

A spherical "micro-nation" in the heart of Vienna.

The most peaceful "country" in the Middle East.

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

A set of 27 bamboo tubes creates an eerie soundscape that changes with the wind.

The world's only museum devoted to the wonders of fluorescence.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

The freshest fish here are the ones you catch yourself.

Go through the looking glass in Tokyo's Wonderland-themed shop.

This secret Swiss fortress is disguised as a harmless pink house, complete with fake windows.

This architectural beauty is the home to a personal collection of more than 600 examples of mechanical musical instruments.

A micronation on an islet along the coast of a Portuguese island.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

This record shop and unofficial black metal museum is an ode to Oslo's heaviest musical export.

Thousands of miniature bronze sculptures have taken over this city square creating a unique art installation.

A kaleidoscopic warehouse-maze of handmade neon signs.

A Parisian boutique devoted to la Sape, the elegant Congolese fashion subculture rooted in European colonization.

What looks like a normal building is really a hollow facade hiding a subway vent.

This frog-themed restaurant was frequented by Picasso, Saint-Exupéry, and more.

This banal Parisian entranceway is not what it seems.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.