Sky History2 Germany invades Poland, sparking global war: Japan expands in Asia and Africa's colonies become key battlegrounds for power and resources. 2026-08-11 From the destructive Viking axe to the sacred but deadly Samurai katana, razor-sharp blades wielded by fearsome warriors have spilled blood and forged empires. 2026-08-11 Posing as a drug dealer, undercover informant Tony Tait infiltrates the secret biker club to take down leader Sonny Barger and meth cook Kenny Owens. 2026-08-11 Could Earth's deepest caves hide secret conduits to other worlds? Or harbour evidence that aliens once visited our planet? Experts investigate. 2026-08-11 Are we being watched by otherworldly beings? Experts make surprising discoveries as they explore the ancient past for evidence of alien overseers. 2026-08-11 A look at the possibility that life began on Mars and travelled to Earth. Plus, if aliens exist, what plans do they have in store for us? Experts investigate. 2026-08-12