World War I
By 1914, trouble was on the rise in Europe, and many countries feared invasion from others. For example, Germany was becoming increasingly powerful, and the British Empire saw that as a threat. Countries formed alliances to protect themselves, but that divided them into two groups. Germany and Austria-Hungary had been allies since 1879 and formed the Triple Alliance with Italy in 1882. France and Russia became allies in 1894 and later formed the Triple Entente with Britain.