The dress is a photograph that became a viral phenomenon on the Internet in 2015. Many people who see the same dress cannot decide if the color is black and blue, or white and gold. The phenomenon showed differences in human colour perception. Within a week, more than ten million tweets had mentioned the dress, using hashtags such as #thedress, #whiteandgold, and #blackandblue. Although the dress has been confirmed to be black and blue, there is still a debate about the true color.