The bombings of Hiroshima and Nagasaki killed an estimated 200,000 people instantly, and many more died later from radiation exposure and injuries.
Biological weapons, which utilize pathogens or toxins, have the potential to kill millions, depending on how they are deployed.
Chemical weapons, such as mustard gas used in World War I, are designed to kill or incapacitate through inhalation or skin contact with toxic agents.
These weapons cause not only instant death from burns and explosions but also long-term destruction through the collapse of infrastructure and cities.
They are designed to be buried underground and detonate when stepped on or disturbed.
Cluster bombs release numerous smaller explosives (submunitions) over a wide area.
Machine guns revolutionized warfare by allowing soldiers to fire rapidly and continuously at targets.