Nixon's visits to China and the Soviet Union were examples of détente, a period of improved relations between the United States and the Soviet Union that occurred during the Cold War. Détente began in the late 1960s and lasted until the late 1970s. During this time, the two countries signed several agreements aimed at reducing tensions and avoiding nuclear conflict, including the Strategic Arms Limitation Treaty (SALT I) and the Anti-Ballistic Missile Treaty (ABM Treaty). Détente also saw an increase in trade and cultural exchanges between the United States and the Soviet Union.