In front of the portraits of supreme leader Ayatollah Ali Khamenei, right, and late revolutionary founder Ayatollah Khomeini, left, a long-range, S-300 missile system is displayed by Iran&#39;s army during a parade marking National Army Day at the mausoleum of the late revolutionary founder Ayatollah Khomeini, just outside Tehran, Iran, Sunday, April 17, 2016. (Ebrahim Noroozi/AP Photo)