Final answer:
The longest hostage crisis at a US Embassy was the Iranian Hostage Crisis, where 52 Americans were held for 444 days in Iran from 1979 to 1981, culminating in their release timed with President Reagan's inauguration.
Step-by-step explanation:
The Longest Hostage Crisis in US History at a Prison:
The longest hostage crisis at a US embassy occurred during the Iranian Hostage Crisis, a pivotal moment in modern history. After the Iranian Revolution, on November 4, 1979, Iranian students seized the US Embassy in Tehran, taking fifty-two American hostages. These individuals were held for an unprecedented 444 days, which became a significant international incident that lasted until January 20, 1981. The crisis began in a climate of fear among Iranians that the US might reinstate the recently deposed Shah, who had entered the United States for medical treatment.
The hostage-taking was endorsed by Iran's new leader, Ayatollah Khomeini, as a strategy to consolidate power and counter internal and external opposition. The hostages were eventually released the moment President Ronald Reagan was inaugurated, after long negotiations that involved the unfreezing of Iranian assets held by the United States.