A debate over the color of a dress went viral last week. That’s right. A picture of a striped dress that looks like it belongs on clearance at Dillard’s was responsible for dividing the nation.

Why did #TheDress trump more important current events such as the debate over LGBT rights in Kansas or the huge snowstorm that was supposed to hit the northeast part of the state all because dress is seen as black and blue to some, and white and gold to others.

The debate supposedly started on Tumblr after a woman was frustrated about the color of a dress she saw at a wedding in early February. She posted the picture and soon enough there were debates all over Twitter, Instagram and Facebook for a solid 24 hours. Everyone had his or her opinion about the dress and it did not take long for #TheDress to become a trending topic.

Why do people see the dress differently? One theory explains that it depends on the number of blue cones a person has in his/her eyes. If viewers have more blue cones, they are more likely to see the dress in black and blue, but viewers with fewer blue cones may perceive the dress to be white and gold.

Another theory states that it depends on the brightness of the screen the person is looking at, and that looking at the dress on an iPhone rather than a computer could sway a person’s perception.

According to one bizarre theory, seeing black and blue might mean that someone is more depressed.

Only two things are known for sure: the dress has lace and it is a crazy optical illusion.

Some people may have accepted that they may never know what the true colors of the dress are, but it truly is black and blue.

The dress was from a retailer in Birmingham, England, called Roman Originals. The design director confirmed that the dress is royal blue with black lace. According to the company website, #TheDress is now back in stock after it sold out during the hype. It is selling for 50 British pounds or $76.98. The dress also comes in other color combinations in case more confusion is necessary.