Complex sentence: "The Dress" is a 2015 viral Internet phenomenon in which people see different colors in a photograph of a dress that was posted to Tumblr by Caitlin McNeill of Scotland.
Split into simpler sentences: The Dress is a 2015 viral Internet phenomenon in which people see different colors in a photograph of a dress. The original picture was taken posted to Tumblr by Caitlin McNeill of Scotland.