Projection Mapping coolness

Been wanting to post this for a while now. There have been some really good use of this technology recently.
What is projection Mapping you ask? Well, according to the almighty Wikipedia, it “is any method of mapping three-dimensional points to a two-dimensional plane.” So basically, an artist is able to match video to the building (surface) that they are projecting on, so graphics, effects are added on, and make the building look like its crumbling, or morphing into something else and so on.
It’s probably easier to see that to explain. Check it out below.

A cool simple one:

A more intricate one:

Another by Nokia, where people can even interact with the graphics: