Remember the blue or gold dress that took the internet by storm? Even though our brains are wired to make sense of what we see, our eyes can play tricks on us.
According to the National Institute of Heath's (NIH) Eye Institute, "an optical illusion is something that plays tricks on your vision."
But not everyone experiences visual images in the same way because of the workings of the brain.
The optical illusion phenomenon was discovered by Celeste McCollough in 1965. She found that staring at colourful gratings for an extended period of time has the potential to affect vision for months.
Here are 10 of the most amazing optical illusions guaranteed to give you brain a workout.