S1, E9: Roman warfare was relentless, but what was their secret weapon? What kind of radios did the military use in WWII? While rockets can cover great distances with extreme accuracy, how were they first used in combat?

S1, E9: Roman warfare was relentless, but what was their secret weapon? What kind of radios did the military use in WWII? While rockets can cover great distances with extreme accuracy, how were they first used in combat?