Vortex-shaped aquarium hosts Europe's largest school of piranhas and other ocean creatures.

This sublime architectural marvel is a rare example of an expressionist church.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

A fascinating insight into daily life in the Eastern Bloc.

A surreal museum of extraordinary industrial objects.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

The anatomical-pathological collection of a man who changed surgery.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Located in the thermoelectric factory that once powered the entire city, this Portuguese museum is shockingly fascinating.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A flamboyant five-story building in Bulgaria resembles a crawling snail.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

An artist's mausoleum with a haunting echo.

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

A curious collection dedicated to human and animal anatomy and pathology.

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

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

The history and future of cannabis.

Pre-Nazi swastikas adorn the sculpted pachyderms flanking this brewhouse portal.

The oldest amusement park in the world has been providing a nice spot to have some fun since the 1500s.

An abandoned lighthouse awaits its destiny: being buried under shifting sand.