The path to the world's most wanted terrorist began with a tip from a Guantanamo detainee. Last August, U.S. intelligence officials discovered a compound in Pakistan, a bustling city of about 90,000 people about 100 miles north of the capital of Islamabad.
It turned out that Bin Laden may not have been hiding in a cave after all. He was essentially hiding in plain sight in a $1 million compound with 12-to 18-foot walls with no telephones or Internet lines, located near a military training facility for Pakistani army cadets.
The mysterious, trusted courier linked back to Bin Laden's location was identified as Sheikh Abu Ahmen, born in Kuwait.
President Barack Obama said it took months to run this thread of information to ground.
Just after midnight in Pakistan, 30 to 40 Navy SEALs flew across the border from Afghanistan on two U.S. helicopters. They dropped down onto the roof on ropes, secured the building and then a firefight ensued.
Inside, rooms were ransacked and computer hard drives were seized by the U.S. military.
Osama Bin Laden refuses to surrender
Bin Laden was ordered to surrender but he refused. The Navy SEALs shot him in the head, likely a "double tap," meaning two shots to ensure he was dead. One bullet hit him in the head above his left eye, the other was a shot to the chest.
"It was a very risky operation, a very courageous decision to do it," ABC News consultant Richard Clarke said. "The intelligence who did this, the military people who did this were spectacular, and the courage of the president to make this very risky decision has to be commended."
Senior administration officials said no one prior to the 40-minute attack was 100 percent certain that Bin Laden was at that location. But by 7 p.m. ET on Sunday, Obama was told there was a high probability Bin Laden had been killed by U.S. forces.
A few hours later, the president addressed the nation with the news.
"A small team of Americans carried out the operation with extraordinary courage and capability. No Americans were harmed. They took care to avoid civilian casualties. After a firefight, they killed Osama Bin Laden and took custody of his body," Obama said.
The president said Monday the world was a safer place without Bin Laden, proudly declaring the killing of the world's most hunted terrorist "a good day for America."
Identifying Osama Bin Laden
Bin Laden's identification process was a quick one. His DNA was matched with that of one of his sister's who died in Boston and whose brain was kept by the United States in the event that authorities needed to make a positive ID.
Two of the women at the compound identified Bin Laden after he was killed, officials told ABC News, and after the SEALs got back to Jalalabad, they measured the corpse, and he was over 6 foot, 4 inches.
The SEALs also transmitted photographs back to CIA headquarters, and agency analysts did facial recognition analysis, which concluded with a 90-to 95-percent match.
Osama Bin Laden's remains
A U.S. official said Bin Laden was buried at sea overnight in accordance with Islamic law, and reportedly to avoid his burial site becoming a shrine. Two Pentagon officials said Monday that Bin Laden's at-sea burial was videotaped and that it probably will be publicly released soon.
The officials also said photos of the body prior to its disposal in the North Arabian Sea on Monday may be released as well. The officials spoke on condition of anonymity because decisions on releasing the materials were pending.
One of Bin Laden's sons also killed
Officials said three adult men were also killed in the raid, including one of Bin Laden's sons, who was a senior member of Al Qaeda. They also said a woman was killed, but it was unclear if she was used as a human shield, or if she was just caught in the crossfire.
This operation was actually plan B. Sources told ABC News that in March, the president authorized a plan for two U.S. B1 Stealth Bombers to drop 2,000-pound bombs on Bin Laden's Abbottabad compound.
However, Obama backed off because the operation would reduce the compound to rubble and destroy all evidence - including the proof that Bin Laden was killed.
It was not clear whether the firefight in which U.S. forces are said to have shot Bin Laden to death was videotaped.
Authorities said the administration was still deliberating on release of the material. Making it public might satisfy those who would otherwise doubt that it was Bin Laden who was killed.
War on Terror continues
During Sunday's address, the president was quick to acknowledge that Bin Laden's death does not mark the end of the war on terror, saying there's no doubt Al Qaeda will continue to target the U.S. and that the country must remain vigilant.
Security officials added that U.S.-born radical cleric Anwar al-Awlaki, who is part of Yemen's Al Qaeda branch, is still at large.
A top Al Qaeda ideologue has promised revenge for Bin Laden's death.
The commentator, going by the online name "Assad al-Jihad2" posted Monday on extremist websites a long eulogy for Bin Laden and promised to "avenge the killing of the Sheik of Islam."
He also announced that anyone thinking the jihad had ended just had to "wait a little bit."
There already is speculation as to who will replace Bin Laden. Many say that his deputy, Ayman al-Zawahri, could take over. He's been running Al Qaeda operations for years, ever since Bin Laden cut himself off from the outside world.
People around the world celebrate Bin Laden's death
The stunning end to the manhunt for Bin Laden sparked celebrations around the world.
In New York City, the news was met with a huge spontaneous gathering. Thousands took to the streets well into the early morning hours. A large crowd also gathered at ground zero in celebration. Some there were climbing on top of light poles and waving American flags. Bin Laden created the Al Qaeda terror network that was responsible for the 9/11 attacks on the U.S.
A similar scene played out at the White House. People there danced on Pennsylvania Avenue and waved American flags. They sang the "Star Spangled Banner" in unison and chanted "USA, USA."
Reaction from U.S. presidents
Former President George W. Bush released a statement Sunday night: "Earlier this evening, President Obama called to inform me that American forces killed Osama Bin Laden, the leader of the Al Qaeda network that attacked America on September 11, 2001. I congratulated him and the men and women of our military and intelligence communities who devoted their lives to this mission. They have our everlasting gratitude. This momentous achievement marks a victory for America, for people who seek peace around the world, and for all those who lost loved ones on September 11, 2001. The fight against terror goes on, but tonight America has sent an unmistakable message: No matter how long it takes, justice will be done."
Former President Bill Clinton released a statement Sunday night: "I congratulate the President, the National Security team and the members of our armed forces on bringing Osama Bin Laden to justice after more than a decade of murderous Al Qaeda attacks."
White House officials told ABC News that President Obama is heading to Ground Zero, likely Thursday, to honor those killed on Sept. 11 and mark the killing of Bin Laden.
ABC News and the Associated Press contributed to this report.