kayjay.

The main causes of World War I were Militarism, Alliances, Imperialism, and Nationalism.
 * WWI**:

When the war ended in November 1918, the war still wasn't over. A peace treaty had to be made and signed. In January 1919, delegates from 27 countries went to France to attend the peace conference. The conference took place at the Palace of Versailles. The treaty made with Germany was named the Treaty of Versailles