What you are seeing here is not the result of a fog machine, but there is an actual cloud in this building.
This was an idea from architect Testuo Kondo, and he got a company called Transsolar to create the actual cloud within the building. The cloud is created with three layers of air pumped at different humidity levels and temperature points, and then used in machines in order to create this cloud that floats in the midst of all this space.
I have a video of it after the jump, but be warned, it is not in English. Not only does it take technology to make this cloud, but it requires tech to keep it in its position, which is “just about a meter above the head of the visitors”.
I noticed that the pillars and walls are made of stone. I am guessing that having a cloud in a building is an insurance nightmare. After all, putting a cloud in a building would definitely “weather” the interior. I can’t believe that I just said that.
Speaking of weather, is it possible to seed the cloud, so it rains? Man, that would be awesome to have an actual raincloud inside. Better yet, how about a thunderstorm?