If History decided to greenlight a second season...

...what subject could be used? All I could think of so far were...

-Fighter Jets
-Bombers
-Sniper Rifles
-Personnel protection equipment (Kevlar, Dragon Skin, Helmets, etc.)
-Explosive
-Naval warships
-Less than lethal weaponry and ammo (rubber bullets, tasers, etc.)
-Future Weapons
-Hand to hand combat/martial arts that are taught to the US military

Anyone else have any good ones?