The human brain is the most complex organ of any species, but that doesn’t mean it can’t be easily tricked.
In the following video, you’ll be asked to stare at the black dot in the center of a photo of a castle. If you keep staring at the dot after the false color image has gone away, and the black-and-white photo returns, you’ll be surprised to see the castle in full color (even though it isn’t)!
According to Metro, the illusion occurs because staring at the false color desensitizes the cone cells responsible for color, so when the black-and-white image returns, the cells need time to readjust, causing the castle to appear in full color.
Read more: http://www.viralnova.com/castle-illusion/