Singles Day — celebrated on Nov. 11 — has become a massive online retail, bringing in more than the online sales of Black Friday and Cyber Monday combined.

Alibaba turned the holiday into the annual shopping event in a bid to boost sales on its e-commerce platform. Last year, it generated a whopping $25 billion in sales — all in just a 24-hour period of purchases.

That's a staggering figure, considering Cyber Monday in the U.S. generated $6.59 billion, while Black Friday saw $5 billion in online sales that same year.

Other retailers have also jumped on the bandwagon.

Alibaba's rival, Chinese e-commerce giant JD.com, generated $19 billion of sales in an 11-day period centered on Singles Day. Even American tech giant Amazon is promoting Singles Day now, sending out emails about the holiday in Singapore.

How did it get so big?

In 2009, Daniel Zhang, Alibaba Group's current CEO, launched the concept of offering discounts to consumers on Singles Day. The event, though, can be traced back even earlier, and is believed to have been started in 1993 at Nanjing University for students as a way to celebrate being single.

Fast forward to 2017: At its peak, Alibaba handled 256,000 transactions per second, and more than 775 million parcels were shipped from orders generated in that 24-hour period.

That growth can be partly attributed to China's huge population of nearly 1.4 billion people, as well as the rising middle-class that increasingly uses smartphones.

Alibaba has also taken advantage of China's mobile-first market by live streaming events featuring celebrities and hosting fashion shows that appear on numerous social media platforms as well as several Chinese TV networks.

Last year, Alibaba brought in celebrities including Nicole Kidman and Pharrell Williams to help with its midnight countdown to Singles Day.