Through 1918-1922 the Ottoman Empire went through a period of power loss due to the impending attack of the Allied forces which led to it's fall, this collapse started October 31, 1918 and ended November 1, 1922
The Holocaust was the most horrific Genocide in history because it contained the murder of 8.5 million people during WW2 or World War 2 this started from January 30, 1933, to May 8, 1945
The Zionist movement was when Jews were trying to find a new homeland or re establish a Jewish state for the historic land of Israel
On Novemeber 2, 1917 the Balfour Declaration was passed which meant that the Jews had an offical right to a homeland or sacred ancestral home.
Many Jews thought thought that they needed to find a "Holy Land" so that they may worship god there. Also the Jews wanted to find the holy land that their ancestors came from.
The Arabs and Palestinian Jews had a fight over some land called Gaza. At first it was a little skirmish but than developed into a full scale civil war. This all began in 1947 and ended 1948.