Pete Buttigieg faced pushback on the debate stage Thursday night for a recent lavish fundraiser in California's Napa Valley. The private event in what's known as a "wine cave" included a chandelier studded with 1,500 Swarovski crystals and $900 bottles of wine — items Senator Elizabeth Warren was quick to point out as being out of reach for voters of more humble means.

Wine caves are meant to age and store wines and are used worldwide in the industry. What's less common is the Hall Rutherford caves functioning as a venue for high-paying donors to support Buttigieg's presidential aspirations.

"Billionaires in wine caves should not pick the next president of the United States," Warren said during the debate.

Here are some photos of the Buttigieg fundraiser in Napa -- with the famous wine cave and the chandelier with 1,500 Swarovski crystals -- that @BrianSlodysko wrote about.https://t.co/0sprQ3aDsy pic.twitter.com/3waO6jO93L — Teddy Schleifer (@teddyschleifer) December 16, 2019

Buttigieg was quick to fire back, slamming Warren for "issuing purity tests" he claimed she was unable to pass. He said candidates couldn't afford to turn down donations, even from billionaires, if they were interested in truly combating Donald Trump.

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During the debate the Warren campaign issued a statement further rebuking Buttigieg's defense of the wine cave fundraiser. "A president was impeached last night because of corruption," communications director Kristen Orthman said.

"A Democratic nominee running on a defense of billionaires and lavish fundraisers in crystal wine caves, and in defense of the corrupt system that wealthy donors fuel, is a terrible risk for Democrats and very likely going to lose."

The back-and-forth regarding high-level donors ultimately ended when Senator Amy Klobuchar remarked that she'd never been to a wine cave, only a wind cave in South Dakota.

The fundraiser appeared to be part of a larger issue for the Buttigieg campaign, which came under fire for holding closed-door events in which press were not allowed. The campaign reversed the practice last week.