The biggest shopping day on the planet raked in an eye-popping $25.4 billion.

Chinese e-commerce giant Alibaba (BABA) said Saturday that sales soared past $18 billion after just 13 hours of the retail blitz known as Singles Day, eclipsing the $17.8 billion it managed in the full 24 hours last year.

Singles Day, a bonanza of online spending in China, has for years racked up more sales than Black Friday and Cyber Monday combined.

Earlier in the day, Alibaba said eager shoppers had managed to spend $1 billion in just 2 minutes.

As the clock struck midnight in Shanghai, the final sales tally rang in at $25,386,927,848, marking about a 40% increase over last year's record-setting sales total.

Singles Day started out as an informal holiday in China celebrating single people on a day that epitomizes not being paired off: 11/11. Alibaba turned it into a festival of discount deals in 2009.

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Alibaba has used the now-massive event to lure international companies onto its platforms. More than 40% of the brands taking part this year came from outside China, according to research firm eMarketer Retail.

And while Singles Day still mostly targets Chinese consumers, it's also increasingly spreading to other countries, experts say.

Local players in Southeast Asia like Lazada (an Alibaba subsidiary), Zalora and Shopee launched their own Singles Day promotions this year, said Xiaofeng Wang, an analyst with research firm Forrester.

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The event is also evolving beyond its original conception as an online shopping spree.

Alibaba and its main Chinese rival, JD.com, have both made significant investments in brick-and-mortar businesses. And they're using the popularity of Singles Day to drive shoppers to offline stores, too.

Cosmetics giant L'Oreal (LRLCF), for example, set up an interactive mirror at its Shanghai store where shoppers could try on virtual makeup using augmented reality and then order products on a touch screen linked to an Alibaba platform.

But beyond the blockbuster sales, Singles Day also creates an enormous amount of waste.

Greenpeace said the manufacturing, packaging and shipping linked to the event produced 258,000 tons of carbon dioxide emissions last year. It would take about 2.6 billion trees to absorb it all.

The environmental activist group estimates this year's shopping blitz is on track to leave an even bigger carbon footprint.

"More over-consumption means more CO2 emissions and waste," said Greenpeace campaigner Nie Li.