Mexico City’s Zócalo square played host to its latest massive event, as some 30,000 people attended a free boxing class on Saturday – setting an unofficial new world record.

Coaching the class was legendary Mexican boxing champion Julio César Chávez, who led the crowd in the opening round. Former champions Irma “The Whirlwind” García, Erika “Dynamite” Cruz, and Ana María Torres also led sessions at the World Boxing Council-sanctioned event.

Chávez, who is 60 years old, is considered to be one of the greatest Mexican boxers of all time. He began the class by ringing a bell, warning the crowd “We will keep it simple, but hold tight, because I’m going to make sure you work.”

There were also messages of support for the participants from Hollywood star Sylvester Stallone – best known for his iconic role as battling boxer Rocky Balboa – and World Heavyweight Champions Floyd Mayweather Jr. and Evander Holyfield. Last year’s mass boxing class, which had an attendance of 14,299, was certified as a Guinness World Record, and that figure has been doubled this year. Since this year’s class was open to children as young as four years old and saw many participants in wheelchairs, the session was not eligible to take the official title again – though WBC President Mauricio Sulaimán said they would try for the record next year.

“The truth is that the number of people is impressive, it reminds me of the Azteca Stadium,” Chávez told Fox Sports. “I am happy and proud of all these young and not-so-young people who are here in the Zócalo.”

“Being around young people gives you energy, and they surround themselves with us, the older adults, since they see that we continue to give our best and we can inspire them,” José Luis Pérez, a 70-year-old attendee, told Reuters. Organizers say that the event will take place every year to help promote boxing and recreation in the city. Smaller events will take place in community centers across the capital on a more regular basis. 

With reports from Aristegui Noticias and Excelsior