Multiple people were injured Friday when a brawl broke out in Justin Herman Plaza. The above video shot by a vendor who sells t-shirts shows some of the carnage (before she ducks to hide).
The fight remains sort of a mystery. KTVU reports that groups of skateboarders, who do frequent the plaza, were primarily involved, using hammers, skateboards, and even easels as weapons.
By the time police arrived, four had been injured, including two who were taken away in an ambulance. At least one vendor was injured when he tried to intervene others turned on him, destroying part of his display.