Baseball games are on hold until further notice, but fans can delve into the history of America’s favorite pastime via a surprising source—MetMuseum.org. The Metropolitan Museum owns thirty thousand vintage baseball cards, and fifteen thousand of them are online (including the four above, from 1933). They were donated by Jefferson R. Burdick, a New York electrician who died in 1963. Although it’s believed that Burdick never attended a game, he invented a catalogue system that’s still used by collectors today.