Los Angeles (CNN) The term "wine cave" was thrown around repeatedly Thursday night at the Democratic presidential debate during an exchange over how Pete Buttigieg is funding his campaign.

Here's why: The South Bend, Indiana, mayor headlined a fundraiser earlier this month in Rutherford, California, at Hall Wines, a winery owned by Kathryn Hall, who was the US ambassador to Austria from 1998 to 2001, and her husband, Craig.

Part of the event took place in a so-called "wine cave" under a chandelier of 1,500 Swarovski crystals.

Photos were posted online of Buttigieg sitting beneath the chandelier, leading to him being roundly mocked for the event and adding to the criticism he has taken for headlining top-dollar fundraisers.

"So the mayor just recently had a fundraiser that was held in a wine cave full of crystals and served $900-a-bottle wine," Sen. Elizabeth Warren of Massachusetts said on Thursday.

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