Singles' Day is the world's biggest online shopping event. It occurs on 11th November every year (the "singles" idea comes from the number of 1's in the date) but originated in Nanjing University in 1993 before spreading to other universities as a way to celebrate being single. It became the global shopping event it is now when Alibaba began offering special discounts on this day in 2009. It has gone bananas since then!