Strange Facts Behind Friday the 13th's Bad Rep

Today is Friday the 13th. Do you know what the fear of the number is called? Triskaidekaphobia. 

Why do people think the number 13 is unlucky? It could have a biblical origin -- Judas, who betrayed Jesus, was the 13th disciple to sit down at the table for the Last Supper. That's long before the Friday the 13th slasher movies saw the light of day.

Here are some unfortunate events that have helped give Friday the 13th a bad reputation:

- Sept. 13, 1940 -- Buckingham Palace in London was hit by a bomb during World War II.

- Jan. 13, 1989 -- A deadly virus crashes IBM (IBM) - Get Report computers, losing valuable data.

- Sept. 13, 1996 -- Rapper Tupac Shakur dies of wounds from a drive-by shooting.

- Jan. 13, 2012 --  The Costa Concordia cruise ship hits a reef off the coast of Isola del Giglio in Italy and starts to sink.