At 8:30 am on September 11th, The World Trade Center opened just like it typically did. 16 minutes later the North tower was hit by hijacked airplanes. 9 minutes later, at 8:55 am The South Tower is declared safe. Though at 9:59 am the PAPD has everyone start to evacuate The World Trade Center. At 9:03, The South Tower was hit, 17 minutes after The North Tower. The President, George W. Bush was alerted of the attacks at 9:05. He was reading a story to an elementary school in Florida at the time. At 9:37 the Pentagon was crashed into.  All flights were grounded at 9:42, almost an hour after the first attack. The South Tower fell at 9:59. At 10:03 another plane, that was going to attack the white house, crashed when the passengers attacked the hijackers. None of the passengers survived. At 10:15 part of the Pentagon collapsed.  13 minutes later The North Tower goes down. At 11:02 Lower Manhattan was evacuated. At 5:20 pm the rest of The World Center was destroyed due to the fire. At 8:30 pm on September 11th, exactly 12 hours after The World Trade center had opened, the president gave a speech. He talked about what happened and said he would punish the terrorists and anyone who helped them. 

Sources: https://timeline.911memorial.org/#Timeline/2