Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.

Walk in the footsteps of the gods and straddle two tectonic plates.

An encyclopedic collection of mammal penises.

Rising from the sea like a stone monster.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

An enormous playhouse designed to look like 21 stacked Lego bricks, with another 25 million colorful Legos inside.

This secret collection of the strange and occult was rediscovered in a forgotten room of an old house.

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

From Coke II to Google Glass, this exhibit features some of the most spectacular commercial flops.

A Very Low Frequency transmitter you can tune in on your PC.

A memorial to a Swedish hockey player's "encounter" with aliens.

This pirate-broadcasting-tower-turned-restaurant played a rebellious role in the history of Dutch television.

Peek through a transparent pyramid and drink in the mountain made of books.

This subterranean studio is filled with fascinating kinetic art.

The patron of this extravagant Art Nouveau confection insisted that nothing less than a boat should project from its facade.

A visionary precursor to the Internet made of index cards.

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

From Tintin to the Smurfs, Europe's greatest graphic icons are celebrated in a grand Art Noveau gallery.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

Climb inside an iron crystal magnified 165 billion times its normal size.

Lavish royal estate punctuated with heated greenhouses.

The television series' iconic giant foot was borrowed from this classical painting.

Hidden beneath the streets of London is a secret subway that only carried mail.

A concrete Picasso in the middle of a student housing complex on the outskirts of Stockholm.