Lucky 13

"The number 13 has been unlucky for centuries. Some historians peg the superstition to the thirteen people who attended the Last Supper (neither Jesus nor Judas came out of that one OK), but ancient Babylon's Code of Hammurabi omits the number 13 in its list of laws, so the superstition dates back to at least 1700 BC. Thirteen is so unlucky, in fact, that in 1881 an organization called The Thirteen Club attempted to improve the number's bad reputation. At the first meeting, the members (all 13 of them) walked under ladders to enter a room covered with spilled salt. The club lasted for many years and grew to over 400 members, including five U.S. presidents: Chester Arthur, Grover Cleveland, Benjamin Harrison, William McKinley and Theodore Roosevelt. Despite the club's efforts, triskaidekaphobia (that's fear of the number 13) flourished; even today, most tall buildings don't have a 13th floor." - Claire Suddath from Time.com