1948–1967 - Ongoing skirmishes between Israel and its Arab neighbors.
1964 - The Palestine Liberation Organization is established in opposition to Israel’s existence. For the next quarter century, under the leadership of Yasser Arafat, it wages a campaign of violence.
June 1967 - In what Israelis call the “Six Day War,” Israel conducts a pre-emptive attack against Egypt and gains control over territory formerly controlled by Egypt, Syria, and Jordan. Israel gains control over the Sinai Peninsula and Gaza Strip from Egypt, the Golan Heights from Syria, and the West Bank and East Jerusalem from Jordan. In six days, Israel roughly triples the size of the territory under its control. Israel begins establishing settlements in Gaza, the Sinai Peninsula, and the West Bank, which many Israelis consider the biblical lands of the Jewish people. Palestinians view the Jewish settlement of these lands as a violation of international law regarding territory seized during war.
In response to the war, the UN Security Council passes Resolution 242, which calls for the “withdrawal of Israeli armed forces from territories occupied in the recent conflict [in official UN languages other than English the article “the” precedes “territories,” thus implying that Israel has to return all the conquered territory]; termination of all claims or states of belligerency and respect for and acknowledgement of the sovereignty, territorial integrity and political independence of every state in the area and their right to live in peace within secure and recognized boundaries free from threats or acts of force.” This resolution, with its formula of “land for peace,” is the basis of for all subsequent peace negotiations between Israel, Palestinians, and the surrounding Arab states.