The history of the world consists of how different groups of people divided, organized and unified. Competing for control is a social characteristic that resulted in cooperation and conflict between groups.
After centuries of developing countries have organized themselves and now we have a primary political division of the Earth that is by state sovereignty. A big example of cooperation among groups of countries is the United Nations, that unite countries to solve problems and help each other.
Also, there were Regional Alliances among nations for the military - NATO for example - political or economic reasons, for example, Europe Union, MERCOSUL and others.
There are bad results from conflicts among different groups or nations, such as wars, terrorist attacks, urban riots, and other problems. But mostly we can see that we have more profits from cooperation than problems with conflicts. There is no country in the world that is 100% self-sufficient in all products, all countries need to import something and export something and this creates a good environment that avoids world conflicts and helps to solve regional ones.
The Byzantine Empire, Holy Roman Empire
