In 2015, a photograph of a dress went viral, dividing viewers over whether its colors were blue and black or white and gold. This optical illusion highlighted differences in human color perception Eleven years ago, a single photo posted on Tumblr sparked one of the biggest internet debates of all time. The dress instantly divided the world, some swore it was white and gold, The Dress Debate Black and Blue or White and Gold British Vogue British Vogue The gold blue dress controversy: Challenging Assumptions