As the country looks back at those terrible events that unfolded 20 years ago on September 11, 2001, most of us will remember where they were and what they were doing on the morning that America was attacked. 

Much has changed since that day, but without a doubt, those events changed the way we live, work, and how we look at things around the world. 

Here’s a look at the timeline of that horrible day, in New York City, Shanksville, Pennsylvania, and the Pentagon, where despite the terrible events, we saw the very best in America’s first responders, many of whom died while rushing to rescue fellow Americans.

5:45 a.m. – The hijackers pass through security in Portland, Maine, and board a flight to Boston, where they connect to American Airlines Flight 11.

7:59 a.m. – Flight 11 takes off from Boston for Los Angeles. Eleven crew members, 81 passengers, including five hijackers are on board.

8:15 a.m. – Flight 175 takes off from Boston for Los Angeles. Nine crew members, 56 passengers, including five hijackers are on board.

8:19 a.m. – The first casualty of 9/11 occurs when a hijacker stabs Daniel Lewin a passenger who is seated in front of him. The hijackers then take control of the aircraft and kill the pilots. Flight 11 crew members alert the FAA that a hijacking has occurred. 

8:20 a.m. – American Airlines Flight 77, takes off from Washington, DC, for Los Angeles. Six crew members, 58 passengers including five hijackers are on board.

8:24 a.m. – While attempting to use the intercom to talk with passengers, a hijacker (Mohamad Atta) instead, contacts air traffic control, thereby alerting air traffic controllers to the hijacking. Atta says, “we have some planes… just be quiet and you will be okay.”

8:37 a.m. – Boston air traffic control alerts the military 18 minutes after receiving notification of the hijacking from crew members. Air National Guard jets in Massachusetts are mobilized to follow Flight 11.

8:42 a.m. United Airlines Flight 93 takes off from Newark for San Francisco after a ground delay. Seven crew members, 37 passengers, including four hijackers are on board.

8:46 a.m. – Flight 11, traveling at approximately 465 mph and carrying an estimated 10,000 gallons of jet fuel, crashes into floors 93 through 99 of the North Tower of the World Trade Center.

8:50 a.m. – President George W. Bush is alerted while reading a book to elementary school students at Sarasota, Florida. His advisors assume this is a tragic accident.

8:55 a.m. – The South Tower of the World Trade Center is declared secure.

8:59 a.m. – New York Port Authority Police, acting quickly, order the evacuation of both towers. One minute later, the order is expanded to the entire World Trade Center complex.

9:00 a.m. – A flight attendant from Flight 175 alerts air traffic control that another hijacking is underway.

9:03 a.m. – Flight 175 speeds up to about 586 mph and crashes into floors 77 through 85 of the South Tower with 9,100 gallons of jet fuel. Some aviation analysts later conclude that the aircraft was in danger of breaking up given the speed it was traveling which was far above the safe limit when flying below 10,000 feet. 

9:05 a.m. – In the now-famous video, President Bush blanches when he learns that a second plane has crashed into the World Trade Center, cementing the fact that it was an act of terrorism. He addresses the American people 25 minutes later, saying that “terrorism against our nation will not stand.”

9:05 a.m. – Onboard Flight 77 passenger Barbara Olson calls her husband, U.S. Solicitor General Theodore Olson, who alerts the FAA and the FBI that a third hijacking has occurred.

9:35 a.m. – President Bush and his staff leave the Bradenton elementary school en route to the Bradenton International Airport to board Air Force One.

9:36 a.m. – Vice President Dick Cheney is evacuated by the Secret Service to the Presidential Emergency Operations Center beneath the White House.

9:37 a.m. – American Airlines Flight 77, accelerated to 530 mph, crashes into the Pentagon. While diving on the Pentagon, the plane is seen by a passing Air Force C-130 who identified it as a “silver 757 or 767.” It clips several telephone poles and the right wing of the aircraft hits a portable generator. The resulting crash and fire kill 59 on the plane and 125 on the ground.

9:42 a.m. – The FAA orders all flights to be grounded.

9:45 a.m. – The White House and U.S. Capitol are evacuated.

9:54 a.m. – Air Force One takes off from Sarasota, without a clear destination. President Bush wants to return to Washington but his staff recommends flying to Barksdale AFB in Louisiana due to its secure location

9:59 a.m. – The South Tower of the WTC collapses in about 10 seconds after burning for 56 minutes. More than 800 people in and around the building are killed.

10:03 a.m. – United Airlines Flight 93 crashes near Shanksville, Pennsylvania, after passengers and crew storm the cockpit. Forty people on board, including the hijackers, perish. The passengers made 37 phone calls from the aircraft and were aware that the World Trade Center had been hit twice by hijacked planes. They rushed the cockpit in hopes of taking over the plane from the hijackers. Passenger Todd Beamer was recorded as saying, “Are you ready? Okay… Let’s roll.”

10:15 a.m. – The Pentagon’s outer ring collapses.

10:28 a.m. – The North Tower of the World Trade Center collapses after burning for 102 minutes. More than 1,600 people in and around the building are killed.

11:02 a.m. – New York City Mayor Rudy Giuliani orders the evacuation of Lower Manhattan.

11:45 a.m. – Air Force One with President Bush onboard lands at Barksdale AFB.

12:16 p.m. – The last flight still in the air above the continental United States lands. U.S. airspace has been cleared of 4,500 flights.

12:30 p.m. – A group of 14 survivors emerge from a North Tower stairwell that was protected from the collapse. The group that amazingly survives includes 13 first responders and one civilian.

2:53 p.m. – President Bush arrives at Offut AFB, Nebraska, he will leave there at 4:36 p.m.

3:00 p.m. – A survivor, Pasquale Buzzelli, is rescued from the rubble of the North Tower. Buzzelli had been evacuating the building and was between the 13th and 22nd floors when the towers collapsed. He was found in the rubble 15 feet above the ground.

5:20 p.m. – After burning for hours,  the 47-story 7 World Trade Center building collapses, There are no casualties as the people were evacuated earlier that morning.

6:54 p.m. – President Bush, after landing at Andrews AFB, arrives back at the White House.

8:30 p.m. – President Bush addresses the nation from the White House. “Today, our fellow citizens, our way of life, our very freedom came under attack in a series of deliberate and deadly terrorist acts… The search is underway for those who are behind these evil acts… we will make no distinction between the terrorists who committed these acts and those who harbor them.” That last line will shape the United States’ foreign policy and lead to its involvement for the next 20 years in Afghanistan.

10:30 p.m. – Rescuers locate PAPD officers Will Jimeno and John McGlouthlin injured but alive in debris of the World Trade Center. Jimeno is freed three hours later but rescuers won’t free McLoughlin for another eight hours. The 18th and final survivor, Genelle Guzman won’t be freed until September 12. 

11:30 p.m. – President Bush enters in his journal, “The Pearl Harbor of our generation took place today… we think it was Usama bin Laden.”