The age of edged weapons ended abruptly just before World War I with rifled artillery, such as howitzers which are able to destroy any masonry fortress. This single invention caused a revolution in military affairs and doctrines that continues to this day. See Technology during World War I for a detailed discussion.
An important feature of industrial age warfare was technological escalation - an innovation could, and would, be rapidly matched by copying it, and often with yet another innovation to counter it. The technological escalation during World War I was profound, producing armed aircraft and tanks.
This continued in the period between the end of that war and the next, with continuous improvements of all weapons by all major powers. Many modern military weapons, particularly ground-based ones, are relatively minor improvements on those of World War II. See military technology during World War II for a detailed discussion.
The most notable development in weaponry since World War II has been the combination and further development of two weapons first used in it—nuclear weapons and the ballistic missile, leading to its ultimate configuration: the ICBM. The mutual possession of these by the United States and the Soviet Union ensured that either nation could inflict terrible damage on the other; so terrible, in fact, that neither nation was willing to instigate direct, all-out war with the other (a phenomenon known as Mutually Assured Destruction). The indiscriminate nature of the destruction has made nuclear-tipped missiles essentially useless for the smaller wars fought since. However computer-guided weaponry of all kinds, from precision-guided munitions (or "smart bombs") to computer-aimed tank rounds, has greatly increased weaponry's accuracy.