Atomic/nuclear weapons
The atomic bomb was the first nuclear weapon ever made during World war two and it was the first weapon that have been tested before Hiroshima was under attack.
Invented by French chemist Claude Berthollet, chlorine gas was first used as a weapon by the military during the first World War in 1914. Chlorine gas was first used as a disarming weapon, and later as a fatal poison.
it was the first 'true' assult weapon designed and producted by Germany during end of WW2
Tank will be the answer! The first tank a British "Mark I" fought on September 1916 during the battle of flers- courcellette (one of the battles in world war I )
Although the Germans during World War II were the first to come up with both the concept it never came to light. America was the first nation to make a nuclear weapon.
The use of chemical weapons during the first World War ; see relevant link below .
Gunpowder and canons
'Little Boy' was the code name for the atomic bomb that was dropped on Hiroshima during World War II. This is the first atomic bomb that was ever utilized as a weapon.
The atomic bomb
the single shot rifle with bayonet
The Turtle, which was the first submarine used in combat.
A rock was probably the first weapon used