The government of Iranian Prime Minister Muhammad Mussadeq is overthrown in a coup orchestrated by American and British intelligence agencies. Mohammad Reza Pahlavi is reinstated as the Shah of Iran.
Widespread unrest in Iran forces the Shah to flee. Ayatollah Ruhollah Khomeini, an Islamic religious leader returns to Iran from exile and takes power.
Hostage Crisis Begins
Iranian students storm the United States embassy in Tehran and hold scores of hostages, most for 444 days. The United States cuts all diplomatic relations with Iran and imposes economic sanctions.
The United States stages a doomed attempt to rescue the American hostages in Iran. Eight U.S. servicemen die.
The public learns of an American effort to sell arms to Iran as a way of raising funds for anti-Communist fighters (known as Contras) in Nicaragua.
The USS Vincennes mistakenly shoots down an Iran Air flight over the Persian Gulf killing 290 people.
The United States implements a policy toward Iran and Iraq known as "dual containment" in an effort to isolate both countries and contain their regional ambitions.
Iran elects a new, more reform-minded president, Mohammad Khatami.
"Axis of Evil"
U.S. President George W. Bush refers to Iran as part of an "Axis of Evil."
US alleges Iran is attempting to build nuclear weapons.
An earthquake kills 50,000 people in the Iranian city of Bam. The United States provides direct aid to victims.
Iran elects a new, more conservative president, Mahmoud Ahmadinejad.
Iran resumes uranium conversion. The International Atomic Energy Agency says Iran is violating the nuclear non-proliferation treaty.
President Ahmadinejad sends a letter to President Bush calling for dialogue. No direct response is sent.
The United States say it will join European nations in talks with Iran if Iran agrees to suspend uranium enrichment,
Another Hostage Crisis?
Iran imprisons Iranian-American scholar Haleh Esfandiari.
U.S. and Iran Talk
For the first time in 27 years, officials of Iran and the United States meet face-to-face for Memorial Day talks.
In September, Iran claims it has 3,000 centrifuges working on uranium enrichment just days after an International Atomic Energy Agency report put the number closer to 2,000.
In December, a new U.S. National Intelligence Estimate surprisingly concludes that Iran halted its nuclear weapons program in 2003.
An Opening? The election of Barack Obama as president fuels speculation of an eventual diplomatic opening between the United States and iran.