Singles' Day is the world's largest shopping event.

The event is preceded by a "countdown gala" that was watched by over 400 million people last year.

Last year's sales totaled $17.8 billion — $11.07 billion more than Black Friday and Cyber Monday combined.

If you combined Black Friday, Cyber Monday, and the Super Bowl, the result would be China's Singles' Day.

Held on November 11 each year, Singles' Day was begun two decades ago as a new shopping holiday meant to celebrate those without romantic partners, in a response to Valentine's Day.

But the holiday didn't become the world's largest shopping event until Chinese e-commerce giant Alibaba entered the fray in 2009, offering deep discounts on items as varied as cars and clothes.

Last year, Alibaba recorded $17.8 billion in sales in 24 hours, a nearly 25% increase on 2015's total sales of $14.3 billion. By comparison, Black Friday and Cyber Monday online sales totaled $6.8 billion in 2016 and $5.7 billion in 2015.

In recent years, there have been projections that the day would see over $20 billion in revenue. This year, Alibaba is expected to expand the event's reach internationally and into segments like luxury retail. In total, over 15 million products are expected to be available from 140,000 brands.

But the festivities aren't confined to Singles' Day, also known as the 11.11 Global Shopping Festival for Alibaba. The company's four-hour "countdown gala" preceding the holiday is a massive event in its own right, attracting over 400 million viewers last year, which is over three times the number of people who watched this year's Super Bowl.

The 2016 countdown gala featured global stars like Kobe Bryant and David and Victoria Beckham. Pharell will appear on this year's broadcast.