The seizure of the United States Embassy in Tehran was forseen by the US government and was a result of financial manipulation by the Shah, Chase Manhatten Bank and Henry Kissinger.

THE STORY

The 1953 Iranian coup d’état deposed the democratically elected government of Iranian Prime Minister Mohammed Mosaddeq.

The United States' Central Intelligence Agency (CIA) overthrew the government of the popular Prime Minister Mosaddeq at the request of, and with support from the British government. In what the CIA called Operation Ajax, the U.S. enabled Mohammad Reza Pahlavi to become an authoritarian monarch, who went on to rule Iran for 26 years until he was overthrown in 1979. wiki

The incredibly corrupt and egocentric Shah, ruled with a personal style of dictatorship which offended most of his countrymen.  Wanting to westernize his country he had teams of thugs tear off veils and humiliate anyone not wearing western dress in the cities. He provided Iran's oil at bankruptcey prices to Britain and America; and generally brought this wealthy country to ruin, due his personal extravagences.

Under the Iranian Constitution all loans taken by the government were to be approved by the parliament.  Imperiously overlooking this legality the Shah took out hundreds of millions in personal loans, which he obligated the government to repay.  When he was overthrown; Chase Manhatten Bank and other creditors, backed by Kissinger presssured President Carter to freeze all Iranian assets in the US; about $8 billion dollars.  The new government in Tehran was refusing to repay these personal loans taken out illegially by the Shah; and the Shah was unwilling or unable to repay them.

Iran was in a bind, out $8 billion dollars in 1979 dollars.  What to do?  They had no leverage or means to resolve this dispute, as their money was already frozen in the US and Chase Manhatten was seizing the money due from the Shah's illegal loans.  

Tens of thousands of incensed students and citizens were demonstrating against the United States in the streets; do to American continued support for the Shah. If Carter had only supported the revolution and condemned the Shah for his excess, things would have gone very differently and America would have had a staunch allie in Iran.  The Shah had been so unpopular that the CIA had been maintaining him by paying off the mullahs for years.  These rioters seized the US Embassy in Tehran when the Shah was admitted into the US.  Until then Khomenei was saying: who will you chose, the new government or the finished Shah?  President Carter chose Chase Manhatten and Henry Kissinger; revealing the power of the financial establishment.. 

The Embassy was held while negotiations went on to unfreeze Iran's funds.  When the funds were released, so were the hostages.

The Iran hostage crisis  Chase Manhatten got its money. Reagan got the Presidency. Iran was robbed to pay off the Shah's debts.

The United States got revenge for the hostage incident by instructing their agent; Sadam Hussain, to attack Iran.

Iran lost hundreds of millions and then had to fight an eight year war with Iraq.  A war started at American request and deliberatly kept going; as intelligence information and weapons were fed to both sides by the CIA.

In Iran today the youth are mesmerized by foreign ideas and culture.  The elderly are filled with bad memories.  Soon, it will be time for the youth to take over and begin a new era.  It may take some nudging to bring this about.  Only a new government and system in Iran can reconcile with the US.  The Old Guard in Iran will not do it, and Americans will not reconcile with the Iranian Clerics.

Since that time public opinion has been manipulated in both countries to create a reservoir of fear and hate.  What goes on behind the scenes is very often much different from what is presented to the public.