NATO, or the North Atlantic Treaty Organization, was a mutual protection pact signed in 1949 by many West European countries, plus the US and Canada. It was created to counterbalance the growing Soviet power in the East, and to help deter aggression against any of its cosigners. In response to the formation of NATO, the USSR and many East European countries formed the Warsaw Pact in 1955. At this point, Europe was essentially divided into two sides, with each ready to respond to conflict.