Timeline of the September 11, 2001 attacks

1972: One World Trade Center completed.
1973: Two World Trade Center completed.
1989: Osama bin Laden founds Al-Qaida.
1993: World Trade Center bombing
1995: Operation Bojinka is discovered by Manila police on a laptop computer in an apartment after an apartment fire
1996: The Taliban, a radical Islamic movement, takes control of Afghanistan.
1998: The 1998 U.S. embassy bombings in Kenya and Tanzania occur.
1999: Indian Airlines Flight 814 hijacked. One passenger dies while the others are released.
2000: The USS Cole is bombed in Yemen

Planning and execution

1992 - Mohammed Atta arrives in Germany
1994 - Planning on Operation Bojinka begins in the Philippines
1995 - Operation Bojinka foiled, Said Bahaji and Ramzi Binalshibh arrive in Germany
1996 - Marwan al-Shehhi and Ziad Jarrah arrive in Germany
1997 - Zakariyah Essabar arrives in Germany
1998 - Recruitment of terrorists in Germany starts
1999 - Hamburg cell is fully formed
2000 - 2000 Al-Qaida Summit in Malaysia, "pilots" head to the United States and train in flying schools
2001 - Rest of the hijackers go to the United States, Zacarias Moussaoui comes to the United States and is arrested, other cell members flee Germany

Also the United Nations International Day of Peace for 2001 [1]

8:46 AM: American Airlines flight 11 crashes into the World Trade Center north tower
9:02 AM: United Airlines flight 175 crashes into the World Trade Center south tower.
9:37 AM: American Airlines flight 77 crashes into The Pentagon
10:03 AM: United Airlines flight 93 crashes in Pennsylvania

September 13: The 'Star-Spangled Banner' is played during the Changing of the Guard at Buckingham Palace. Russia observes a minute's silence. See Memorials and services.
September 11 to September 18: more than 540 attacks on Arab-Americans living in the US.
September 20: George W. Bush announces that the USA is at war. See US governmental response.
September 14 to September 21: Worldwide stock markets plummet. See World economic effects.
September 15: CIA director George Tenet presents the Worldwide Attack Matrix.

October 1: Rudy Giuliani speaks to the United Nations General Assembly
October 7: U.S. Attack on Afghanistan commences
November 2001: Uniformed Firefighters Association holds a demonstration against the reduction in firefighters allocated to The Pile.
March 2002: The Tribute in Light project begins.
September 2002: First anniversary memorials and services are held throughout the world, particularly the USA.