We all grow old eventually. But do we really have to? Could humans be immortal one day? Through the work of global leading scientists on three incredible kinds of animal that don’t really age like we do, Lifespan reveals some of the surprising causes of human aging, and what we could do about it. This short documentary takes a personal approach, blending science interviews, laboratory footage and macro photography to get up close with hydras, fruit flies and naked mole rats.