Tanks were the first armored fighting machine to be used on the battlefield. These "land ships", as they were first called, were championed by Head of the British Admiralty Winston Churchill. Adapted from an American tractor with caterpillar tracks, the machine was designed in secrecy to break through the heavily fortified trenches and offer protection for troops that were being mowed down by heavy artillery.
While most people think the Blitz originated in WWII, the truth is that the first Blitz happened during WWI. Bombs were delivered from giant airships designed by Count Ferdinand von Zeppelin, who got his inspiration when he was a Germany Army observer in the US during the Civil War and rode in a hot air balloon for the first time. These lighter than air superstructures, two times longer than the Statue of Liberty is high, measured their flights in hundreds of miles when pioneering aviators measured their success in hundreds of yards.
The Germans, ignoring international treaties they signed, were first to weaponize a chemical. In this case it was chlorine–a highly toxic ingredient used in the manufacture of chemical dyes of which they had a huge supply. Their action unleashed an escalation of poison gas weapons as both sides developed different chemicals and more effective counter measures. Their use of culminated in a bold British plan that unfolded beneath the battlefield at Messine Ridge. British mining and explosive experts planted 450 tons of high explosive hidden in a network of tunnels under Messine ridge. When ignited, they created the biggest land mine in history–killing 10,000 German soldiers. The explosion rattled windows at 10 Downing St., 140 miles away and registered as an earthquake in Switzerland.
The Atlantic became a killing field as German submarines took on the might of the dominant British Navy. The stealth and silent killers were able to sink 5,200 ships by war's end, and nearly brought Britain to its knees. But in their frenzy of attacks, the Germans sink the US passenger liner Lusitania, killing nearly 2,000 on board. American outrage helped President Wilson get Congress to finally agree to enter the war. In the end, the Allied Atlantic blockade forces Germany to surrender, but the submarine was established as an effective military weapon.