march. norah. >> o'donnell: a lot of new headlines. manuel bojorquez, thank you. we want to turn now to chicago, the nation's third-largest school district, where parents of more than 350,000 students are anxiously wondering if their children will be back in school tomorrow. at this hour, the teachers' union and the city are negotiating new covid-related health protocols after the teachers voted to return to remote learning due to the rise in cases last night. well, chicago's mayor called the teachers' action an illegal work stoppage. cbs' charlie de mar reports from chicago. >> reporter: it was a late-night jolt that ground the nation's third-largest school district to a halt and sent parents scrambling to make alternate arrangements for their children. >> i'm not prepared. i did hear about it in the news, but i just kind of assumed that they will find some way around this. >> reporter: chicago mayor lori lightfoot canceled all classes but threw parents a life line. she kept school doors open so children had a place to get