Footage from outside the California Charter Schools Association in downtown Los Angeles shows an absolutely massive turnout for the second day of the teachers' strike on Tuesday.

Thousands congregate bearing placards, chanting, and blowing whistles, dressed in black and red. On Monday, some 32,000 Los Angeles educators walked out and union leaders called for Tuesday's rally to be at least as big as Monday's event.

This is the first teachers' strike in LA in around three decades and follows a wave of similar bouts of collective action in different US cities and states, such as Chicago and West Virginia. However, the Los Angeles strike represents the second largest school district in the US.

The union is calling for the school district to increase staffing levels in the face of unviable class sizes, boost salaries, and resist any steps towards privatisation.