The Iran Hostage Crisis, 31 Years Later -- PICTURES

An armed student patrols the outside of the U.S. Embassy in Tehran, on April 26, 1980, walking past a "Death To Carter" sign on the wall. With the news of the abortive U.S. mission to rescue the hostages, there was a dramatic increase in such security patrols. (AP)

Demonstrators burn an American flag on Nov. 9, 1979, atop the wall of the U.S. Embassy where students had been holding American hostages since Nov. 4. (AP)

This is a general view outside the U.S. Embassy in Tehran, on Nov. 27, 1979, showing demonstrators, including oil tank drivers with their vehicles. They supported the students who were holding 50 American hostages inside the embassy. (MOHAMMAD SAYAD/AP)

Iranian demonstrators burn an effigy of Uncle Sam, branded with CIA on its right arm outside the U.S. Embassy in Tehran, on Nov. 13, 1979, during a demonstration in support of the Iranian militants who took over the embassy on Nov. 4. (AP)

Iranian students holding 50 hostages in the U.S. Embassy in Tehran stage a demonstration, Dec. 15, 1979. (MOHAMMAD SAYAD/AP)

President Jimmy Carter prepares to address the American people on nationwide television from the Oval Office at the White House on April 25, 1980, on the failed mission to rescue the Iran hostages. (AP)

Two Iranians use the U.S. flag to carry garbage out of the U.S. Embassy in Tehran, Nov. 13, 1979. About 60 Americans and 40 other nationals have been held hostage inside the compound since Nov. 4. (AP)

President Carter attends memorial services for eight servicemen killed in the unsuccessful attempt to rescue the American hostages from Iran, at Arlington National Cemetery, Arlington, Va., on May 9, 1980. At right is Army Chief of Chaplains Kermit D. Johnson. (DENNIS COOK/AP)

Freed U.S. hostage David Roeder shouts and waves as he arrives at Rhein-Main U.S. Air Force base in Frankfurt, West Germany from Algeria on Jan. 21, 1981. He was among 52 Americans held hostage in Iran for 444 days after their capture at the U.S. Embassy in Tehran. The sign on the airplane door reads, "Welcome back to Freedom." (AP)

President Ronald Reagan listens as Bruce Laingen, top diplomatic hostage during the Iran hostage crisis, speaks at the offical welcome ceremony at the White House on Jan. 27. 1981. On Jan. 20, Iran released the 52 remaining hostages held at the U.S. Embassy in Tehran for 444 days. (AP)

Former hostage Richard Morefield gets a kiss from his mother, Maria Morefield, as he arrives at Andrews Air Force Base, Md., on Jan. 27, 1981 for the official welcome in Washington for the freed hostages. (AP)