what offically started and ended WWI? and what made the us enter the war?

https://www.google.com/search?rlz=1C2GGGE_enUS379US455&hl=en&source=hp&biw=1366&bih=643&q=wwi+causes+timeline&gbv=2&oq=wwi+causes+&aq=4&aqi=g6g-v4&aql=&gs_sm=c&gs_upl=1305l20042l0l28532l11l11l0l0l0l0l300l1757l0.1.5.1l7l0

https://www.google.com/search?rlz=1C1GGGE_enUS379US379&aq=f&gcx=c&sourceid=chrome&ie=UTF-8&q=us+entry+into+wwi

Read widely and take good notes.

World War I officially started on July 28, 1914, and ended on November 11, 1918. The main event that triggered the war was the assassination of Archduke Franz Ferdinand of Austria-Hungary on June 28, 1914, by a Serbian nationalist. This event sparked a series of diplomatic and military actions among the nations of Europe, leading to a global conflict.

As for the United States' entry into the war, there were several factors that influenced their decision. Initially, the U.S. followed a policy of neutrality and did not actively participate in the war. However, a combination of events eventually led to America's involvement:

1. Unrestricted Submarine Warfare: Germany began targeting and sinking civilian ships, including American vessels, using submarines. One notable incident was the sinking of the British passenger liner RMS Lusitania in 1915, resulting in the loss of American lives.

2. Zimmerman Telegram: In 1917, the British intercepted and decoded a telegram sent by Germany's Foreign Secretary, Arthur Zimmerman, to Mexico. The telegram proposed an alliance between Germany and Mexico against the United States. This revelation outraged the American public and increased anti-German sentiment.

3. Economic ties: The United States had significant economic interests and trade connections with countries involved in the war, especially the Allies (France, Britain, and Russia). These economic ties made neutrality increasingly difficult, and supporting the Allies became more advantageous for the U.S.

4. Woodrow Wilson's idealism: President Woodrow Wilson, re-elected in 1916 with the slogan "He kept us out of war," saw the war as an opportunity to promote democracy and played an active role in attempting to negotiate peace. However, as Germany continued its aggressive actions, Wilson asked Congress to declare war in April 1917, citing the need to "make the world safe for democracy."

To summarize, the direct factors that led the U.S. to enter World War I were Germany's unrestricted submarine warfare, the Zimmerman Telegram, and economic ties with the Allies. Wilson's idealistic vision for world peace further influenced the American decision to engage in the conflict.