Friday the 13th does not happen often – maybe once or twice in a year. In 2010, this will happen only once, on August 13. The number 13 is widely held to be an unlucky number, and Friday has been considered unlucky even way back in medieval times. Combine these two superstitions together, and you have one of the strongest superstitious beliefs ever. A few reasons why … [Read more...] about Why is Friday the 13th considered unlucky?