The answer is Allies
The World War I split nations into two groups, one was known as the 'Triple Entente' which consisted of Britain, France and Russia, while the 'Triple Alliance' consisted of Germany, Italy and Austria-hungry.
When the United States joined World War I, it became part of the Allies, in response to the Axis powers.
Eventually the Allies won the war, which led to the Treaty of Versailles, which again led to World War II
