FILE - In this Feb. 18, 1979 file photo, Palestinian Liberation Organization leader Yasser Arafat, right, kisses Ayatollah Ruhollah Khomeini, left, during a meeting in Tehran, Iran. Forty years ago, Iran's ruling shah left his nation for the last time and an Islamic Revolution overthrew the vestiges of his caretaker government. The effects of the 1979 revolution, including the takeover of the U.S. Embassy in Tehran and ensuing hostage crisis, reverberate through decades of tense relations between Iran and America. (AP Photo, File)