It started in Germany where he was originally from he wanted to kill all of the Jews in Germany then in Europe then the world
Religion was a major cause of the English Civil War. It was part of a Europe wide conflict between Roman Catholicism and Protestantism. At the start of his reign (1625) King Charles I had married the Roman Catholic Henrietta Maria of France.
The United States became more deeply involved in Vietnam in the late 1960s.
Stalin supported the philosophy of communism, while Mussolini supported the philosophy of fascism.