Although he’s trailing Hillary Clinton in the polls, Sen. Bernie Sanders’ (I-VT) support is spreading like a California wildfire. Nearly 10,000 people attended Sanders’ most recent rally in Madison, Wisconsin, reported the Huffington Post. That’s huge.

The Alliant Energy Center in Madison seats 10,231 people. Arena staff said Sanders nearly packed the house as approximately 9,600 were in attendance, by far the largest turnout for any campaign rally in the 2016 cycle, and it’s only July.

In comparison, Democratic frontrunner Hillary Clinton’s largest campaign crowd was half of Sanders’ Wisconsin outing, and Jeb Bush drew a crowd of only 3,000 to his campaign kickoff in Miami. Unlike Clinton, Sanders didn’t charge his supporters thousands of dollars to attend the rally.

Not only can Sanders draw a huge crowd, but he also knows how to send them into a frenzy. His message against big political money and Wall Street was met with roaring applause.

“The big money interests — Wall Street, corporate America, all of these guys — have so much power that no president can defeat them unless there is an organized grassroots movement making them an offer they can’t refuse,” said Sanders, as the crowd cheered. “When you deny the right of workers to come together in collective bargaining, that’s extremism. When you tell a woman that she cannot control her own body, that’s extremism.”

Sanders was referring to Wisconsin Gov. Scott Walker (R), who has made a mission out of busting labor unions and denying women their reproductive rights.

Some in attendance peppered social media with photos of the impressive crowd.