World War One The first world war started for many reasons like competion of the colonies, military technology development, economic competition and different national interests. Many historians believe that Germany caused World War One. But the first world war was triggered on June 28, 1914, when Austrian Empire Franz Ferdinand was murdered by a Serbian nationalist Gavrilo Princip. On July 28, Austria-Hungary declared war on Serbia. After that Germany declared war on Russia and France in the beginning of August. Russia and France became allies. On August 4th The United Kingdom declares war on Germany, after Germany invades Belgium. Austria-Hungary declares war on Russia and Serbia declares war on Germany on August 6. On August 19th President Woodrow Wilson announces the United States will remain neutral. In early November The United Kingdom announces that the North Sea is a military area, effectively creating a blockade of goods into Germany. Allied countries
An alliance is an agreement made between two or more countries to give each other help if it is needed. When an alliance is signed, those countries become known as Allies. But allies changed in the war many times.

The war divided Europe into two armed camps. On one side was the Triple Alliance made up of Germany, Austria-Hungary and Italy, and their enemy was the Triple Entente of France, Russia and Great Britain. As other countries began to join sides, the Triple Alliance became known as the Central Powers and the Triple Entente became the Allied Forces. The more states joined the alliances the more the war spread across Europe. In the beginning of February 1915 Germany declares a "war zone" around Great Britain. (essentially effecting a submarine blockade where even neutral merchant vessels were to be potential targets. ) On May 7th The British ocean liner RMS Lusitania is sunk by