Masked men belonging to various Palestinian factions announced in Hebron on Dec. 15, 2012, the establishment of the National Unity Brigades and the beginning of a third intifada against Israel. Source.
Owen Eugene "Jack" Armstrong, abducted September 16, 2004, beheaded on September 20, 2004.
On September 1, 2014, using a similar method - a cable, a wooden pole, and a car - Tomas Rivera, 51, of Port Jervis, New York, decapitated himself in Hunts Point, Bronx, New York. Source.
Both news reports used exactly the same wording that the men "hit the gas" before killing themselves.
An unnamed elderly woman was beheaded in the garden of a north London, UK, house, and her body found on September 4, 2014. Source.
Members of the Fajr Libya (Libyan Dawn) coalition guard the entrance to the Tripoli International Airport on August 24, 2014.
1970 – A British airliner is hijacked by the Popular Front for the Liberation of Palestine and flown to Dawson's Field (a remote desert airstrip near Zarka, formerly used as a British Royal Air Force base) in Jordan.
2001 – Ahmed Shah Massoud, leader of the Northern Alliance, is assassinated in Afghanistan by two al Qaeda assassins who claimed to be Arab journalists wanting an interview.
2004 – A bomb explodes outside the Australian embassy in Jakarta, killing 10 people.
2012 – A wave of attacks kill more than 108 people and injure 351 others in Iraq.
September 10 ~
1898 – Empress Elizabeth of Austria is assassinated by Luigi Lucheni.
1939 – World War II: The submarine HMS Oxley is mistakenly sunk by the submarine HMS Triton near Norway and becomes the Royal Navy's first loss.
1976 – A British Airways Hawker Siddeley Trident and an Inex-Adria DC-9 collide near Zagreb, Yugoslavia, killing 176.
2000 – Operation Barras successfully frees six British soldiers held captive for over two weeks and contributes to the end of the Sierra Leone Civil War.
2001 – Antonio da Costa Santos, mayor of Campinas, Brazil is assassinated.
2003 – Anna Lindh, the foreign minister of Sweden, is fatally stabbed (assassinated) while shopping, and dies the following day.
September 11 ~
1970 – The Dawson's Field hijackers release 88 of their hostages. The remaining hostages, mostly Jewish and Israeli citizens, are held until September 25.
1974 – Eastern Air Lines Flight 212 crashes in Charlotte, North Carolina, killing 69 passengers and two crew.
1976 – A group of Croatian nationalists plant a bomb in a coin locker at Grand Central Terminal. After stating political demands, they reveal the location and provide instructions for disarming the bomb. The disarming operation is not executed properly, killing one NYPD bomb squad specialist.
2001 – Two hijacked aircraft crash into the World Trade Center in New York City, while a third smashes into The Pentagon in Arlington County, Virginia, and a fourth into a field near Shanksville, Pennsylvania, in a series of coordinated suicide attacks by 19 members of al-Qaeda. Altogether, 2,996 people are killed.
2003 – Swedish foreign minister Anna Lindh dies from her assassination stabbing of the previous day.
2012 – The U.S. embassy in Benghazi, Libya is attacked, resulting in four deaths. U.S. Ambassador J. Christopher Stevens, Foreign Service Information Officer Sean Smith, and CIA contractors and former Navy SEALS Tyrone Woods and Glen Doherty were killed during the series of raids, commencing at nightfall and continuing into the next morning.
There is something special about the number 11 to terrorists, no doubt about it. Such incidents as the 3/11  Madrid, 7/11  Mumbai, and 9/11  terrorist attacks serve as misnamed “celebrity events” that become models copied by other Islamic extremists.
As noted in the opening of my 2004 book The Copycat Effect: How the Media and Popular Culture Trigger the Mayhem in Tomorrow's Headlines, September 11th was the date of an assault by a private plane on the White House, in 1994, although the attack is little remembered today.