The people that was kept hostages for 444 days?
The US Embassy hostages in Iran.
The Iran hostage crisis was a situation in which 52 US citizens were held hostage for 444 days from November 4, 1979 to January 20, 1981, after a group of Islamist students and militants took over the Embassy of the United States in Tehran. The hostages were formally released minutes after the new US president, Ronald Reagan, was sworn in on January 20, 1981. For more information, see the link below.
Iran has not attacked the United States, with two exceptions. It stormed the US embassy in 1979 and took the US delegation hostage for 444 days. Iran also attacked the US covert operatives sent into Iranian airspace to retrieve the hostages since the US craft were in violation of Iranian airspace regulations.