August 17, 1953: Prime Minister Mohammed Mossadegh is ousted after the CIA and British intelligence back a plan to overthrow him. The shah of Iran, Mohammed Reza Pahlavi, becomes the authoritarian monarch.
Above: A crowd of Persian Prime Minister Mohammed Mossadegh supporters, armed with long sticks tear down a statue of Shah Reza, father of the Shah of Iran, in Tehran
March 5, 1957: Iran signs the Iran-United States Agreement for Cooperation Concerning Civil Uses of Atomic Energy, which was part of President Eisenhower’s Atoms for Peace program.
Above: President Dwight D. Eisenhower and Shah Mohammed Reza Pahlevi of Iran pose on Dec. 14, 1959 at Marble Palace in Tehran, Iran following Eisenhower's arrival from India on his 11-nation goodwill tour.
May 15, 1975: President Gerald R. Ford publishes a directive that would "permit U.S. material to be fabricated into fuel in Iran for use in its own reactors." The directive also allowed Iran to buy and operate an American plant to use for extracting plutonium from reactor fuel.
Above: President Ford and Secretary of State Kissinger shake hands at the White House just prior to ceremonies for the State Visit of the Shah of Iran, May 15, 1975.
November 4, 1979: Iranian students seize 63 hostages from the American Embassy and detain 52 of them for 444 days. Their release came a few hours after President Jimmy Carter left office.
Above: One of the hostages seized when Islamic radicals stormed the U.S. Embassy in Tehran, blindfolded and with his hands bound, is displayed to the crowd outside the U.S. Embassy in Tehran by the Iranian hostage-takers on Nov. 9, 1979.
September 22, 1980: Iraq invades Iran, leaving Iran diplomatically isolated from the West, supporting Iraq, for the better part of the decade. A cease-fire wasn't declared until 1988, after an estimated 1 million lives were lost.
Above: Iraqi troops entrenched along the highway connecting Abadan with Khorramshahr on Oct. 19, 1980 while smoke drifting in background comes from an oil refinery near Abadan, which was set by Iraqi artillery bombardment.
Nov. 25, 1986: President Ronald Regan acknowledges sending military supplies to Iran. The shipments were allegedly made in payment for Iran's help to free U.S. hostages in Lebanon.
Above: U.S. President Ronald Reagan tells reporters that "I'm not taking any more questions," during a news conference in the White House briefing room, on Nov. 25, 1986. Reagan announced to reporters the resignation of national security adviser Vice Adm. John Poindexter and the firing of Poindexter's aide Lt. Col. Oliver North.
July 2, 1988: The U.S. Navy cruiser Vincennes accidentally shoots down an Iran Air commercial flight that is on its way to Dubai, killing 290 passengers and crew aboard.
Above: Mourners carry coffins through the streets of Tehran on July 7, 1988 during a mass funeral four days after the Iranian airliner is shot down.
January 8, 1995: Iran announces that it will sign a deal with Russia to construct a nuclear power plant at Bushehr, Iran, which is thought to be the country's most active center for nuclear weapons research and production.
Above: This satellite image shows the Bushehr nuclear power plant, dome in top center, on July 6, 2002 in Bushehr, Iran, 750 miles southwest of Tehran.
August, 2002: Secret Iranian Nuclear Facilities are discovered, including a uranium enrichment plant at Natanz and a heavy water plant at Arak. The United States accuses Tehran of an "across-the-board pursuit of weapons of mass destruction," and Iran signs an accord with Russia to speed up the construction of the nuclear power plant at Bushehr.
Above: Alireza Jafarzadeh, U.S. representative of the National Council of Resistance of Iran, holds a copy of "Islamic Fundamentalism" during a Washington news conference on Aug. 14, 2002 where he discussed his organization's new information of top secret projects of the Iranian regime's nuclear program.
January 29, 2002: President George W. Bush describes Iran, Iraq and North Korea as an "axis of evil" during his State of the Union address, causing an outrage in Iran among conservatives and reformists.
2008: The U.S. works with Israel to launch a secret cyber-attack on Iran's major nuclear complex. In 2010, a worm within the system destroyed 1,000 Iranian centrifuges, but the plant recovered in late 2011.
Above: Iranian technicians work at the Bushehr nuclear power plant, outside the southern city of Bushehr, Iran.
September 25, 2009: The U.S. and Allies declassify intelligence revealing an Iranian effort to build a uranium plant within the enclave of a mountain. Iran is warned against nuclear "deception," but denies the accusation.
Above: President Barack Obama, followed by British Prime Minister Gordon Brown, center, and French President Nicolas Sarkozy, arrive to make a statement on Iran's nuclear facility, on Sept. 25, 2009, during the G-20 Summit in Pittsburgh.
June 15, 2013: Moderate cleric Hassan Hassan Rouhani is elected president of Iran. He says there will be a new era of relations with the West.
Above: Hassan Rouhani was declared the winner in Iran's presidential election on June 15, 2013.
January 12, 2014: Six world powers struck a deal with Iran temporarily freezing much of Tehran’s nuclear program. In exchange, the country would be relieved of Western economic sanctions.
Above: French Foreign Minister Laurent Fabius and British Foreign Minister William Hague speak together while U.S. Secretary of State John Kerry and Jordanian Foreign Minister Nasser Judeh speak together, after a joint press conference at the foreign ministry in Paris, France.