Iran's long border with America's Cold War rival, the Soviet Union, and its position as the largest, most powerful country in the oil-rich Persian Gulf, made Iran a "pillar" of US foreign policy in the Middle East. Prior to the Iranian Revolution of 1979, many Iranian students and other citizens resided in the United States, and had a positive and welcoming attitude towards America and Americans. In the 1970s, approximately 25,000 American technicians were deployed to Iran in order to maintain military equipment (such as F-14s) that had been sold to the Shah's government. Additionally, from 1950 to 1979, an estimated 800,000 to 850,000 Americans had visited or lived in Iran, and had often expressed their admiration for the Iranian people.