Perhaps the most famous war that is still fresh in many older peoples minds and in our history books is the World war 2. World war 2 brought along alot of devastation and whole generations were affected by it. Another famous one is the cold war, which was fought at an ideological level rather than with arms. But it threatened to turn out to a real war at anytime. The two sides were the capitalist nations, mainly United States against the communist mainly then Russia. The communist side has suffered a major blow since the 1980s with the fall of the Berlin wall and the break up of the Russian state.
Wars have been fought for control of natural resources like the wars between settlers from Europe and native american people in America.
In the urban areas of most North American cities, gang wars and dope wars are not rare but frequent occurrences. These wars fights are for the control of areas for drug trafficking and other crimes. Gang wars are fought between crime groups for the control of operation areas. This creates alot of problems for governments and the citizens.