Iranian Hostage Crisis--after the US refused to hand over the Shah, the Iranians stormed the US embassy in Tehran and held the people there hostage for 444 days.
The Shah of Iran fled during the Iranian Revolution and was held safe in the US. The new government demanded the US hand him over to face trials but the US refused. This caused the Iranian rebels to storm the American Embassy and take 52 diplomats and citizens hostage for 444 days.