Floating swimming pool within a moored vessel.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

One man's lifetime collection of tiny objects of wisdom gathered from around the world, on display for public enjoyment.

The darkest building on Earth was built for the snow-white scenery of the 2018 Winter Olympics.

A beautiful but toxic fountain of mercury.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

Caves famous for the dragon-slaying saint who lived there.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

Vines grow up the metal bars in this public park created from an old machine factory.