A weapon, arm or armament is any implement or device that can be used to deter, threaten, inflict physical damage, harm, or kill. Weapons are used to increase the efficacy and efficiency of activities such as hunting, crime, law enforcement, self-defense, warfare, or suicide. In broader context, weapons may be construed to include anything used to gain a tactical, strategic, material or mental advantage over an adversary or enemy target. While ordinary objects – sticks, rocks, bottles, chairs, vehicles – can be used as weapons, many objects are expressly designed for the purpose; these range from simple implements such as clubs, axes and swords, to complicated modern firearms, tanks, intercontinental ballistic missiles, biological weapons, and cyberweapons. Something that has been re-purposed, converted, or enhanced to become a weapon of war is termed weaponized, such as a weaponized virus or weaponized laser. History The use of weapons is a major driver of cultural evolution and human history up to today, since weapons are a type of tool which is used to dominate and subdue autonomous agents such as animals and by that allow for an expansion of the cultural niche, while simultaneously other weapon users (i.e., agents such as humans, groups, cultures) are able to adapt to weapons of enemies by learning, triggering a continuous process of competitive technological, skill and cognitive improvement (arms race). Prehistoric The use of objects as weapons has been observed among chimpanzees, leading to speculation that early hominids used weapons as early as five million years ago. However, this can not be confirmed using physical evidence because wooden clubs, spears, and unshaped stones would have left an ambiguous record. The earliest unambiguous weapons to be found are the Schöningen spears, eight wooden throwing spears dating back more than 300,000 years. At the site of Nataruk in Turkana, Kenya, numerous human skeletons dating to 10,000 years ago may present evidence of traumatic injuries to the head, neck, ribs, knees and hands, including obsidian projectiles embedded in the bones that might have been caused from arrows and clubs during conflict between two hunter-gatherer groups. But the evidence interpretation of warfare at Nataruk has been challenged. Ancient history The earliest ancient weapons were evolutionary improvements of late Neolithic implements, but significant improvements in materials and crafting techniques led to a series of revolutions in military technology. The development of metal tools began with copper during the Copper Age (about