The Palestine Israel war is a conflict over land. Thousands of years ago, Jewish people lived in Israel. They built holy temples like Solomon’s temple and other holy places like Dome of the Rock and the Western Wall. Over time, different people conquered the land (Israel) and took over. First they were conquered by Alexander the Great, then by The Roman Empire, then by Arab and Asian conquests, then they were persecuted by the Christian church in the Crusades. Jewish people had to keep moving to new lands. They moved towards Europe over time. Meanwhile, the land where Israel once was is now called Palestine.
In 1917, the Jewish people were promised land/independence if they helped the Allies win WW1. The allies won this war, so the Jewish people were given back Israel. However, the Palestininan people now lived there.
The two people - Israelis and Palestinians, now fight over the land. Nobody can agree who has the right to be there.
