No need to strap in for a "ride" on this walkable roller coaster.

This is not only one of the oldest collections in Europe, but also possibly the most beautiful.

Hidden in the garden of physicist Erwin Schrödinger's house is a life-size figure of a cat from his famous thought experiment.

One hundred years ago this small house in downtown Zürich became the birthplace of the Dada movement.

A German artist built a home and garden filled with whimsical art pieces, like a massive, operational volcano.

Bursting forth from a historic German neighborhood, these day-glo palaces are now a bright fixture in the town.

A Nazi concentration camp and Anne Frank's place of death.

This gateway to subterranean Hanover plays jazz, pop and rock to surprised passersby.

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

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

The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

It is said a heartbroken man visited the gap every day to stare blankly out at the sea.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

The house where the writer spent his formative years.

400 million years of erosion shaped these fascinating seaside caves, which made an appearance on 'Game of Thrones.'

Amazing vistas await visitors to this stretch of coastline.

Sail in for a ’dam good slice.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

A surrealist timepiece by the artist of melting clocks.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Artwork tucked within the trees greets visitors with surreal sonic experiences.

The birthplace of the builder of the Statue of Liberty is now a museum dedicated to his work.

Today this former Nazi concentration camp stands as a poignant memorial to the victims of fascism, and a warning from history.

An ancient monastery, a locked room, and a mysterious book heist.