Gangster House (Archangelsk, Russia)
Though incomplete, the Gangster House is believed to be the world's tallest wooden house, soaring thirteen floors to reach 144 feet (about half the size of Londons Big Ben). The homeowner or gangster, Nikolai Sutyagin, had all intentions of finishing the construction but his dream went on hold when he got locked up behind bars for his third jail sentence. Now out of jail and out of money, the ex-convict lives at the bottom of this precarious tower of wood.

Free Spirit Houses (British Columbia, Canada)
These wooden spheres can be hung from any solid surface (tree, cliff, bridge, etc.) and are accessed by a spiral stairway or a short suspension bridge. A web of rope grasps onto a strong point, essentially replacing the foundation of a conventional building. You can anchor points on the top and bottom to prevent swinging or just let it loose and enjoy the ride.

Upside-Down House (Syzmbark, Poland)
This upside down design seems totally nonsensicalbut that is exactly the message the Polish philanthropist and designer, Daniel Czapiewski, was trying to send. The unstable and backward construction was built as a social commentary on Polands former Communist era. The monument is worth a trip be it for a lesson in history or balance.

Cactus House (Rotterdam, Netherlands)
Cool-looking would be a good enough reason for us, but this housing design was created to maximize each apartments outdoor space and indoor sunlight. The splaying stack of slabs creates big terraces for gardening and the irregular shape allows sun to enter from multiple angles.

Floating Castle (Ukraine)
Supported by a single cantilever, this mysterious levitating farm house belongs in a sci-fi flick. Its claimed to be an old bunker for the overload of mineral fertilizers but were sure theres a better back story . . . alien architects probably had a hand in it.

Mushroom House (Cincinnati, Ohio)
So disparate in materials and shapes this hodgepodge house looks like its been welded and glued together. But this is no hobo-construction, it was designed by the professor of architecture and interior design at the University of Cincinnati, Terry Brown, and was recently on the market for an estimated $400K.

Cube House (Rotterdam, Netherlands)
Living in a tilted house is much easier than it looksjust ask the people living in these the Kijk-Kubus homes. Architect Piet Blom tipped a conventional house forty-five degrees and rested it upon a hexagon-shaped pole so that three sides face down and the other three face the sky. Each of the cube houses accommodates three floors: a living space including a kitchen, study and bathroom, the middle floor houses bedrooms and the top is the pyramid room that can act like an attic or viewing deck. These houses are quite expensive, but you can satisfy your curiosity by visiting the museum show house.

Extreme Tree House (Irian Jana, Indonesia)
The Korowai and Kombai clans carved out clearings of the remote part of the low-land forest to make way for these extreme tree houses. Unlike the typical tree houses that are nestled in branches, these dwellings are perched on the tip tops of the treesfully exposed to the elements. But we arent sure whats scarier a strong gust of wind or the ladder they use to get up there.

Wozoco Apartments (Amsterdam-Osdorp, Holland)
A zoning law and blueprint flub were the inspiration for this apartment complex. Dutch housing regulations require apartment construction to provide a certain amount of daylight to their tenantsbut MVRDV architects forgot to plan for that. Their solution? To hang thirteen of the 100 units off the north facade of the block. The ingenious design saves ground floor space and allows enough sunlight to enter the east or west facade.

Heliotrope Rotating House (Freiburg, Germany)
Green to the extreme, Architect Rolf Disch built a solar powered home that rotates towards the warm sun in the winter and rotates back toward its well-insulated rear in the summer. A house that spins in circles doesnt sound too stable to us, but for the environment it is worth the risk.