This explains how the blue black white gold dress illusion was possible. But it doesn't explain why some people saw it one way and some saw it the other, and no one seemed to see Ten years ago, a photo of a dress posted on Tumblr sparked a massive debate: was it blue and black or white and gold? Millions argued online, and even celebrities joined in. Scientists later explained I've been thinking about "the dress" for 10 years. Here's what I've learned. 10 years ago, a simple photograph of a dress sparked a global debate unlike anything seen online before. Posted in 2015, the image caused people to argue intensely over whether the dress