Nicolas Schöffer's massive interactive sculpture was assembled in 1961 and brought back online in 2016.

This abandoned Belgian fortress is purposefully being left to nature.

Hiding the longest subterranean river known in the world.

This collection of lurid religious statues tell the tales of a saint who stood down the devil.

The highest point in Belgium is a staircase to nowhere.

A whimsical bridge uses saxophones to pay tribute to two great men and the European Union.

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

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

An art museum with an eclectic design and a scandalous past.

Eduardo Kobra’s breathtaking 32,300-square-foot graffiti wall took over Rio’s Olympic Boulevard.

This massive Brazilian church is built like an angular, technicolor pyramid left by Mayans from the future.

A 125-meter long "tribute to the Brazilian people."

Beautiful public park off the beaten path and away from tourists.

The bears of Bern have been a city highlight for over 500 years.

A fascinating and enormous collection of natural history exhibits stained by a dark colonial legacy.

A jazz band formed by African water animals in the heart of Flemish Brabant.

A magical and peaceful ruined Cistercian abbey in what is now southern Belgium.

An abandoned saucer-shaped monument in the Bulgarian mountains.

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

This historic black and white monastery is one of Bulgaria's architectural jewels.

"Holy Wisdom" overlooks the city that became its namesake.

A vast Communist-era exhibition space in the Bulgarian capital.

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

Longest road tunnel in the world features an air treatment plant and the illusion of daylight.