Friday the 13th is synonymous with bad luck.. some people refuse to fly, make business deals or get married today.

Here are some strange things that happened on Friday the 13th:

Nov. 13, 1970 – A huge storm killed an estimated 300,000 people in Bangladesh, and created floods that killed as many as 1 million in the Ganges delta.

June 13, 1986 – The Olsen twins, Mary-Kate and Ashley, were born, and they are BOTH strange.

Jan. 13, 1989 – The "Friday the 13th virus" infected hundreds of IBM computers across Great Britain, wiping out program files and causing considerable anxiety at a time computer viruses weren't a regular happening.

Oct. 13, 1989 – The Dow Jones Industrial Average underwent the second largest drop it had ever experienced at that time. Nicknamed the Friday-the-13th mini-crash, the Dow dropped 190.58 points that day. That would be nothing today!

Aug. 13, 1999 - would have been Alfred Hitchcock's 100th birthday.

Here are more Strange Things from Friday the 13th