The major technological advancement that changed warfare at the dawn of the 20th century was the machine gun. This weapon revolutionized combat with its ability to fire multiple rounds quickly, significantly increasing the lethality of battlefields. In World War I, its usage contributed to the trench warfare strategy, as soldiers faced devastating consequences when charging fortified positions. Coupled with advances in artillery and the use of poison gas, the machine gun represented a shift towards more industrialized and mechanized warfare, altering military tactics and leading to unprecedented casualties.