The dress above, also known as Dressgate and associated with the hashtags #thedress, #whiteandgold, and #blackandblue, is a viral photo and meme which became popular on the evening of 26 February 2015. The meme originated from a washed-out photograph of a dress posted on the social networking services Facebook and Tumblr—disputing whether the dress pictured was blue and black, or white and gold. In the first week after the surfacing of the image alone, more than 10 million tweets mentioned the dress.

Although it was confirmed that the dress actually was blue and black, the image prompted discussions surrounding the matter across various platforms, with users discussing their opinions on the colour and why they perceived the dress as being a certain colour, while others discussed the triviality of the dispute to begin with. Members of the fields of neuroscience and colour vision provided scientific commentary on the optical illusion. The dress itself, which was identified as a product of the retailer Roman Originals, experienced a major surge in sales as a result of the meme.

It was the photo that shocked the world. Is it white and gold or black and blue? Watch how Ellen got to the bottom of it as she meets all the key players in this internet phenomenon, not to mention the dress itself!

What do you see? Black and Blue? Or White and Gold?