Built at strategic points, and fitted with impressive fortifications and ingenious systems to counter attacks, fortresses are thought to be impenetrable. And yet, certain skillful warlords have successfully stormed them. How did they manage this?
What if the natural world were less selfish than we first thought? Observing tacit alliances, mutual services, secret pacts, and altruistic sacrifices, this blue chip wildlife documentary explores the mysteries of animal cooperation.