Europe's largest natural bridge has a 19th century royal chateau built into its side.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

This weird abode has inspired everything from the "House On Haunted Hil" to a robot hunter's pad.

A bizarre house filled with an astounding array of collections.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

Strange physical sensations and optical contradictions keep visitors coming back for more.

The abandoned "Ghost Mansion" was left to decay in the mountains of Northern Italy.

This faux-seedy Japanese arcade is made up to look like a maze of alleys straight out of a cyberpunk dystopia.

An eerie maze of industrial factories looks like something out of a dystopian sci-fi.

Locals transformed this Canadian evergreen into a secret hangout with spectacular views of Vancouver's skyline.

With well over 130 falls and cascades to brag about, Hamilton, Ontario has earned its stripes as the waterfall capital of the world.

Sleep snuggled in a sphere suspended atop the forest canopy of Vancouver Island.

Secret Swing.

This urban oasis is a marvelous meld of music and landscape architecture.

One of the largest underground systems runs under Canada's largest urban center.

One of the foremost Sherlock Holmes collections is hidden away at a Toronto library.

Lost subway station nestled beneath Toronto's busy commuter line.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

A Hawaiian stairway to heaven—that you can't climb.

This World War II-era bunker is now packed with posters and props from movies and TV shows filmed nearby.

More than 2,000 species of tropical plants call this nature preserve and sanctuary home.