What was the Yom Kippur War?
The Yom Kippur War was the last full war between Israel and one or more Arab states. It occurred in 1973. The main belligerents in the war were Israel on the one side and Egypt and Syria on the other. Many other Arab nations provided military and/or financial help. The Arabs were also aided significantly by the Soviet Union while the United States provided arms to the Israelis after the war started.
The war started with massive Arab surprise attacks on Yom Kippur. This is the holiest day of the Jewish religious calendar. Israeli intelligence managed to miss the signs of the coming attack and surprise was achieved. The Arab attack was initially quite successful. After that, however, the Israelis achieved victory on all fronts. The war lasted about three weeks. It ended largely because the Soviet Union and the United States felt that the situation was becoming too dangerous and that there was a threat of war that would involve the superpowers themselves. They pressured the combatants to institute a ceasefire.
The war ended with no territorial gains on either side. It had many important long-term results, including the making of peace between Israel and many Arab states, most notably with Egypt in the 1979 Camp David Accords.