Saudi Arabia—one of the United States' most important allies for more than sixty years—is home to vast oil fields and a wealthy, often extravagant, monarchy. It is also home to fifteen of the nineteen terrorists responsible for the attacks of September 11, 2001.

Until 9/11, most Americans paid little attention to how the Kingdom of Saudi Arabia was run. But in the aftermath of the attacks, America awoke to some difficult truths about its longtime ally: for decades, Saudi wealth and charities supported individuals and organizations dedicated to doing America harm, and its universities and religious schools—known as madrassas—prepared countless young men for jihad against the West.

Today, Saudi television broadcasts programs where children read poems against Jews and in praise of Islamic martyrs. Recently twenty-six Saudi clerics, among them, Sheikh Nasser al-Omar, issued a fatwa, or edict, encouraging Muslims to fight the Americans in Iraq. And in December 2004, gunmen attacked the American consulate in Jeddah.

"Investigating the history of U.S.-Saudi relations, it quickly becomes clear that this is an alliance built on quicksand," says co-producer Martin Smith, who has reported from the region for previous FRONTLINE films including "Saudi Time Bomb?" and "In Search of Al Qaeda."

It was Franklin Roosevelt, seen in rare archival footage conducting a top-secret World War II meeting with Saudi King Abd al-Aziz on board the USS Quincy, who established the basic principles behind the U.S.-Saudi alliance.

"America struck a pact with Saudi Arabia, and the deal was very simple," says Youssef Ibrahim, former Middle East bureau chief for The New York Times. "You give us oil at cheap prices, and we will give you protection. This protection eventually evolved into an American hegemony over the entire Gulf region, that this was an American area of influence, and in return for this it shall be protected from all enemies."

As history shows, this agreement between Saudi Arabia's royal family and the U.S government has been challenged time and again by Saudi Arabia's fundamentalist Islamic population, who distrust American influence and intention and oppose America's alliance with Israel.

Resentment against the royal family also grew following the oil embargo of 1973, when massive amounts of wealth—and an influx of Western goods and services— challenged Saudi Arabia's deeply religious and traditional society.

In 1979, the region erupted. In nearby Iran, Islamic fundamentalists overthrew the Shah in a bitterly anti-American revolution. That same year, a band of militants in Saudi Arabia attacked and occupied the holiest of Islam's holy shrines, the Mosque of Mecca. After a bloody twenty-one day siege, the militants were defeated and sixty-three were beheaded. "It was a warning bell that the ship of state had drifted," says Islamic cleric Nasser al Omar.

Desperate to maintain leadership, the royal family reacted quickly.

"We killed the extremists of 1979," says liberal Saudi Arabian columnist Sulaiman al-Hattlan. "But a few months later we adopted their ideology. We gave them what they wanted. We started competing on how to appear more conservative just to protect our reputation."

"House of Saud" also tells the story of the 1990 Iraqi invasion of Kuwait and the arrival in the kingdom of American troops to fight the war against Saddam.

"As the American forces started coming in, there were voices that spoke of an invasion by these people," says Khaled Al Maeena, editor-in-chief of Arab News. "[They said] they're defiling the country…they will make us change our religion, or…make us doubt our way of life."

When Iraq was driven from Kuwait, U.S. troops remained in Saudi Arabia. The presence of U.S. troops became the chief rallying cry for the most famous of all Saudis, Osama bin Laden.

Bin Laden's anti-American and anti-royal fatwas struck a note with many Saudis. And after 9/11, American attitudes changed as well.

"When it became clear that fifteen of the nineteen [terrorists] were Saudis, that was a disaster," says Adel Al-Jubeir, foreign affairs advisor to Saudi Crown Prince Abdullah. "Bin Laden, at that moment, had made in the minds of Americans Saudi Arabia into an enemy."

Offering context and perspective for understanding the country of Saudi Arabia in 2005, this report also illuminates the challenges this nation faces in the future.