America's largest four-year public university system, California State University, announced Tuesday that classes at its 23 campuses would be canceled for fall semester, with instruction taking place almost exclusively online. As The New York Times notes, Cal State is the first large American university system to tell students they will not be returning to campus in the fall. Most of the nation’s colleges and universities have gone out of their way to say they intend to reopen, but they are also making backup plans for online classes. McGill University in Montreal, one of Canada’s most prestigious universities, made a similar announcement on Monday, saying it will offer most of its courses online in September.