Optical illusions are older than you think. The first optical illusions date back to 20,000 BC and took the form of cave sculptings. Nowadays they are found all over the place – on screens, in books ...

Check out some of these optical illusions, below — and see how you perceive images placed before your eyes. Just how do optical illusions work? "From an evolutionary standpoint, optical illusion is ...

In one go, this image might look pretty simple, but is it? The grid is filled with black dots, but if you stare for a little longer, the brain begins to play tricks on you. This illusion works because ...