CNN iReport

To many people, the number 13 brings bad luck because there were 13 people at the last supper. Another story comes from Norse mythology. One of the last Norse Gods, "Loki" crashed a party at Valhalla, the banquet hall of the Gods.

There were 12 guests there until Loki arrived, then things turned grim, he was number 13...The story goes that "Balder" the god of light,joy and reconciliation, died when Loki tricked Balders sightless brother "Hod" into throwing mistletow at him. Just like Kryptonite to Superman, Mistletow, you see was the only thing on earth that could kill Balder.

Agatha Christie, the famous mystery writer (1890-1976) actually capitalized on the superstition regarding the number 13. She wrote 13 short stories and put them in a book called "The 13 Problems".  After that, she did it again, she wrote "Thirteen at Dinner".

13 will always remain a mystery to us.There are many truths about the number. For example, it is a prime number. This means that it is only divisible-without there being a remainder- by the number 1 and itself.

13 is also a "Fibonacci" number. This can be defined as "a number that is the sum of the two preceding numbers". If you begin with 0 and 1,the sequence would run, (0,1,1,2,3,5,8,13,21,34,45,79) and so on.