Designed as a labyrinth, this subterranean prison was crafted without bars or doors.

A tunnel with windows, so you don't miss out on the impressive views.

This hidden 13th-century tavern room has a few Shakespearean connections.

An Oxford museum where visitors can have tea with the Mad Hatter and climb through the wardrobe to a fantasy land.

This Norman castle was once the site of a Victorian-era prison, and now exists as a luxury hotel.

A crazy maze of a hostel, where every trap door and secret entrance brings you to a new wacky, wonderful room.

In the middle of a remote desert town is a surprisingly opulent hotel.

These pillars at the main entrance of this church are actually a hidden musical instrument.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

A cheeky reminder about the value of art dangles above one of Olomouc's busiest streets.

A rooftop restaurant hides in plain sight atop Vienna's Palace of Justice.

The oldest stone house in Paris was built by its most famous alchemist.

Numerous sculptures set along hiking trails symbolize and idealize the relationship between man and nature.

To fit bodies into this Renaissance crypt, they were first left to decompose in the crypt's rotting room.

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

A colossal sculptural lion built by the same man who designed the Statue of Liberty.

This peculiar Italian elevator runs both horizontally and vertically.

A star-shaped fortress town fort built in the geometric model of the Renaissance utopian city.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

A science fiction-inspired apartment building designed by a famous Spanish architect.

An isolated village literally built into the crevices and rock formations of a mountain.

A tiny, forgotten park of surrealist sculptures in Angouleme.

The vibrant buildings in the “capital of the comic strip” celebrate the art form that made it famous.

The bizarre home and sculpture garden of an eccentric artist.