Optical illusion colour or Black and white?

I just came across this really cool website that show those brain tricking optical illusions.

Try this on. Is the castle colour or black and white?

http://www.youtube.com/watch?v=w6ccBwnc5KU&feature=player_embedded

Lots of other great tricks at this site .

http://io9.com/5690012/the-webs-best-optical-illusion-videosand-how-they-trick-your-brain?ref=nf