By Granth Vanaik (Reuters) – Black Friday? No. Cyber Monday? Nope. Prime Day? Absolutely not. The world's biggest shopping event happens in China each year – and it's called Singles Day. Originally a holiday to celebrate being single, as a counter to Valentine's Day, the event has grown into a weeks-long online shopping festival that peaks on Nov. 11. WHEN DID THE IDEA OF SINGLES DAY ORIGINATE? The idea for Singles Day had originated at China's Nanjing University back in 1993 and was originally called "Bachelor's Day." On the day, single people treat themselves with gifts and presents, while also…