It is often said that if one does not learn history, it is doomed to repeat itself. The study of history can also be seen as a science. The more we study it and the events that occurred, the more predictable history can become. It is possible to see history as "a dynamic, relative process in which one small force can affect an entire system." In a sense, one action of one individual can affect entire countries, systems, and people for years to come.
An example of this was when the Arch Duke Ferdinand was assassinated in 1914. As a result, war was declard on Serbia by Austria-Hungary eventually launching the world into World War II.