Two weeks before he would launch the invasion of Iraq, President Bush announces at a press conference that time is running out on the UN inspections process and on Saddam Hussein

President Bush delivers his final ultimatum: "Saddam Hussein and his sons must leave Iraq within 48 hours. Their refusal to go will result in military conflict commenced at a time of our choosing."

Coalition troops, massed in the Persian Gulf on the eve of the invasion, fully expect an Iraqi chemical attack as they near Baghdad. 200,000 ground troops, almost all of them American and British, are backed by an armada of ships in the Gulf and hundreds of Navy and Air Force warplanes.

At the insistence of Defense Secretary Donald Rumsfeld, the ground force is only half the size of the force that ejected Iraqi forces from Kuwait in 1991.

Zero hour. The coalition plans to begin the invasion with a spectacular opening "decapitation" strike, targeting the top 55 men in the Iraqi leadership. But in Washington there is a sudden change of plans -- CIA chief George Tenet has received a tip on where Saddam Hussein would be that very night. In a meeting with President Bush and the national security team, the decision is made to launch a surprise strike aimed at Saddam. The planned attacks on the full Iraqi leadership are abandoned.

Stealth bombs and cruise missiles hit the target in the grounds of the Dora Farm complex where Saddam's daughters live. But the intelligence tip is inaccurate -- Saddam is not there.

The invasion begins. General Franks's ground war plan is for the Army's 5th Corps to cross the Iraq-Kuwait border and attack Baghdad from the desert west of the Euphrates.

The Marine Corps will attack through the inhabited areas east of the river, by heading toward Nasiriya to cross the Eurphates and make a parallel advance.

The British, with support from U.S. Marines, will secure Iraq's second city, Basra.

Secretary Rumsfeld is upbeat, convinced the Iraqi people will assist the invasion: "There will be Iraqis who offer not only to help us but to help liberate the country and to free the Iraqi people. More of them there are, the greater the chance that the war will be limited and less broad."

The coalition launches its bombing campaign in Baghdad against Saddam's palaces and ministries. The spectacle is designed to convince the Iraqi people that it is safe to overthrow the regime.

American commanders advancing across the Kuwait border report Iraqi regular forces are simply falling apart, taking off uniforms and disappearing among the civilian population.

The British reach the outskirts of Basra but are met with resistance from regular troops and the Fedayeen, a fiercely loyal militia headed by Saddam's son Uday. Saddam's most feared lieutenant commands Basra: Ali Hassan Al Majid, known as "Chemical Ali." The British close off the city but allow civilians to leave. British MI6 agents inside Basra hope they can incite an uprising. Some in the American high command are exasperated. They feel British caution makes Saddam look strong. But the British want to minimize civilian casualties.

The port of Um Qasr at the head of the Persian Gulf is captured by U.S. Marines. It's the first time since World War II that U.S. Marines are operating under British command.

By nightfall in Iraq, the forward elements of the 3rd Infantry are over 150 miles inside Iraq and roughly halfway to Baghdad.

U.S. combat operations are meeting with resistance in a number of locations, the most significant around the city of Nasiriya where U.S. Marines plan to capture two bridges to cross the Euphrates. A unit from the 507th Maintenance Company supporting the U.S. Army's advance takes a wrong turn in the pre-dawn darkness and stumbles into Nasiriya behind enemy lines. The Fedayeen strike. Eleven Americans die and seven are taken prisoner, including a badly wounded Private First Class Jessica Lynch.

In a separate attack in Nasiriya, U.S. Marines fiercely battle Iraqis. An American aircraft arrives to help but attacks the American position, adding to the casualties. Eighteen Marines die, some 50 are wounded. Many Iraqi civilians are also killed. By the end of the day a total of 29 Americans die in Nasiriya, and with them dies hope that the Iraqi people will help the coalition overthrow the regime.

In the western desert, fast-moving 5th Army troops are advancing towards four Republican Guard divisions -- perhaps 40,000 men hidden in the countryside south of Baghdad. Thirty-two Apache helicopters are ordered forward this night to search out and destroy the Guard. The Iraqis spring an ambush and intense small arms fire brings down one Apache. The rest are forced to turn back with almost every helicopter damaged. The Republican Guard is largely unscathed. Apache pilots' faith in U.S. intelligence is badly shaken.

The battle for Basra rages between the British 7th Armored Brigade and Iraqi regulars and militia. British troops pull back to avoid an expected Republican Guard ambush and they are willing to wait so as to avoid a civilian bloodbath. Their wait will last for two weeks.

In the Shiite holy city of Najaf, units of the U.S. Army's 3rd Infantry Division engage in fierce battles witlh Iraqi forces and paramilitary.

By now, there have been more setbacks: A brutal three-day sandstorm has been swirling across southern Iraq and Fedayeen fighters are leaving the cities and attacking supply lines of the lead units. Five days into the invasion, the American advance on Baghdad stalls.

Back in Washington, retired generals have been appearing on television and commenting that the war is not going as well as it should because there are not enough combat forces on the ground.

American forces encircle Najaf after several days of intense battles.

Paratroopers from the U.S. Army's 173rd Airborne Brigade land in northern Iraq to open the battle on the northern front. The 173rd and Special Operations troops begin operating with Kurdish forces in the north, calling in air strikes when Iraqi forces try to move forward.

The American army prepares to attack Baghdad. Lead units will have to funnel through a mile-wide gap between a lake and the city of Karbala -- the so- called Karbala Gap -- and then assault across the Euphrates towards Baghdad. A signals intercept leads to a warning alert to coalition troops -- be prepared for imminent chemical attack.

British Royal Marines launch Operation James, the single largest British operation of the war, in an effort to secure Basra.

After more than two days of a tank, artillery and plane barrage, the U.S. Army's 101st Airborne Division begins the final securing of Najaf.

Just before dawn, members of the 3rd Infantry advance into the Karbala Gap. There is no chemical attack. Iraqi forces have pulled back because they feel too vulnerable in open desert. The Americans now begin to advance toward the Iraqis main defensive positions on the eastern bank of the Euphrates.

The Iraqi commander in the area, General Raad Al-Hamdani, is summoned to Baghdad for a meeting with Saddam's son Qusay. He says he was told, "All what happened in the last two weeks was strategic deception and the main enemy action will come from north of Baghdad." Hamdani protests, saying the Americans are attacking in the south, but he must obey. That evening, however, with the Americans now controlling the bridge over the Euphrates and U.S. tank crews in new positions east of the Euphrates, Hamdani is ordered to turn his units round and counterattack. He musters his most elite troops, a brigade from the Republican Guard's Medina Division, but the battle turns into a slaughter. Not a single American is killed. No one knows how many Iraqi soldiers died.

Troops from the 3rd Infantry reach Saddam International Airport on the western outskirts of Baghdad. On the morning of April 4th, the Iraqis counter-attack and the Americans come face to face with the teenage fanatics of the Baghdad Fedayeen. Most of the Fedayeen are killed.

But the Americans aren't yet ready for the final assault on Baghdad. They still fear what is left of the Republican Guard and wonder where they are. It turns out the key Guard units had been positioned due south of Baghdad; the American advance had simply bypassed the bulk of them. Before the battle for Baghdad can begin, a brigade is dispatched south to deal with them.

Hidden in dense palm groves to avoid detection from the air, the U.S. forces find the most powerful armored division of the Iraqi army. The U.S. had been bombing the wrong positions. But the American advance to Baghdad has been so fast, the Iraqis are caught by surprise -- with the U.S. forces now coming upon them from the north, most Iraqi tanks are facing the wrong way. In the ferocious battle the follows, the Medina Division simply melts away.

At dawn, in a surprise armed reconnaissance raid into Baghdad, Col. David Perkins's 2nd Brigade, 3rd Infantry makes the first "Thunder Run" into the city, driving straight up Highway 8 and taking intense fire.

The Americans encounter morning traffic and many Iraqi defenders are dressed in civilian clothes. American troops are not always successful in distinguishing fighters from civilians. By late morning the Americans have sliced through Baghdad's south-western suburbs and arrive safely back at the airport.

Meanwhile, in Basra the British slowly are tightening the screw. On an intelligence tip, coalition planes try to assassinate "Chemical Ali." But the F-16 strike misses him and kills 17 civilians. It proves a turning point, however, since many in Basra now believe Chemical Ali is dead.

The British 7^th Armored Brigade rolls into Basra. At last, the coalition is greeted with celebration by Iraqis. But looting soon begins. The British expected the police, army, and civil administration to be intact and to help run the city. But with the regime gone, everything crumbles. The British haven't planned for this and it is a taste of what is to come.

In Baghdad U.S. Marines now join the American 5th Corps and are given the job of storming the east of the city. Marine commanders anticipate serious resistance, but the Iraqi army is retreating in chaos.

Approaching Baghdad, U.S. Marines storm the Diyala Bridge near the eastern boundary of the city. Fanning out on the northern bank, they are jittery and fear suicide bombers. Warning shots are fired at vehicles approaching the bridge. If a car doesn't stop, it's riddled with bullets. About a dozen civilians die that morning at the Diyala Bridge.

It takes some time for the Marines to realize that the eastern side of Baghdad is virtually defenseless.

On the west side, a second "Thunder Run" is made by Col. Perkins. He decides to head straight downtown for Saddam's palaces, spreading panic among the Iraqi defenders. Two tank battalions are followed by more 3rd Infantry who are to take and hold three key cloverleafs -- code-named Moe, Larry and Curly -- to secure the road for resupply trucks. Fighting at these interchanges is intense; the fiercest is at Curly.

Colonel Perkins spends the night in Saddam's palace. Nineteen days after crossing the Kuwait border, less than a week after the breakthrough at the Karbala Gap, the Americans have penetrated to the very heart of the regime.

That afternoon the Americans get another intelligence tip on Saddam Hussein: he is in the wealthy Al Mansour district in the west of Baghdad. But the intelligence passed to the Stealth bomber pilots is not precise. The Americans miss again and 18 civilians are killed.

U.S. forces secure Baghdad after final desperate resistance by Fedayeen and Ba'ath Party militias who are fighting almost alone. The regular Iraqi Army soldiers don't fight or even surrender en masse, as the Americans hoped; they simply go home.

Late in the afternoon of April 9, in Baghdad's Firdos Square, the statue of Saddam Hussein is pulled down.

American columns continue to roll into Baghdad. But there are few of the triumphal scenes Americans had hoped for. The people of Baghdad are wary, suspicious. And as in Basra, looting spreads quickly.

Mosul falls to Kurdish peshmerga and U.S. Special Operations forces.

Television images of looting and chaos dominate American newscasts in the days following Baghdad's fall. At a briefing this day, Defense Secretary Rumsfeld reacts bitterly to suggestions the military is not in control of the situation and in a statement dealing with looting, says, "… freedom's untidy and free people are free to make mistakes and commit crimes and do bad things…."

After a few days of inaction, U.S. troops begin cracking down on looters.

General Tommy Franks, the commander of the invasion, flies into Baghdad to congratulate the American commanders on their swift victory over Saddam Hussein.

But in the weeks that follow, a violent insurgency grows against coalition forces.

President Bush lands on the deck of the USS Abraham Lincoln off the coast of California and announces the official end of combat operations in Iraq.

The insurgency grows in the weeks and months that follow, flowing into the vacuum left by the collapse of authority. In the Sunni Triangle around Baghdad, remnants of the Fedayeen, the Ba'ath Party, foreign Islamic fighters, and even ordinary Iraqis wage a guerrilla war against the occupiers of Iraq.

The losses will mount on all sides. Less than 150 American troops were killed in the allied invasion. As of February 26, 2004, almost 400 have died in the aftermath.