We stumbled upon this insane architectural treasure when searching on craigslist for 17 bedroom homes. 'House NA' has the giddy imagination of a treehouse and the sleek aesthetic of a futuristic space station. It was made by Tokyo architectural group Sou Fujimoto, which specializes on conceptual and residencial spaces with a Japanese flair. There are see-through walls, ladders galore and infinite nooks and crannies, although they could, perhaps, use a 'welcome' mat. Take a look at the hottest real estate in Tokyo in the video below.