From The Dress to legless women, the internet is filled with optical illusions that are both accidental and intentional.

While new optical illusions go viral all the time, here are some of the most famous illusions that have kept us scratching our heads for years.

Optical illusions are older than you think. The first optical illusions date back to 20,000 BC and were seen in caves. Nowadays they are found all over the place – on screens, in books and even in ...

A supposedly 3D optical illusion has been posted online and is possibly the most divisive I've ever seen on the optical illusion. Comments are either steadfastly denying any effect whatsoever, with ...

"3D Schröder Staircase" created by Japanese mathematician Kokichi Sugihara. Best Illusion of the Year Contest/YouTube The Best Illusion of the Year Contest chose a mind-boggling winner in its 2020 ...