9/11 was a catastrophe. On September 11, 2001, 19 militants associated with the Islamic extremist group al Qaeda hijacked four airplanes and carried out suicide attacks against targets in the United States. Two of the planes were flown into the twin towers of the World Trade Center in New York City, a third plane hit the Pentagon just outside Washington, D.C., and the fourth plane crashed in a field in Shanksville, Pennsylvania. Almost 3,000 people were killed during the 9/11 terrorist attacks, which triggered major U.S. initiatives to combat terrorism and defined the presidency of George W. Bush. The US had not witnessed any urban devastation during the second World War but it was its worst nightmare to have an attack on mainland USA. On September 11, 2001, at 8:45 a.m. on a clear Tuesday morning, an American Airlines Boeing 767 loaded with 20,000 gallons of jet fuel crashed into the north tower of the World Trade Center in New York City. The impact left a gaping, burning hole near the 80th floor of the 110-story skyscraper, instantly killing hundreds of people and trapping hundreds more in higher floors. As the evacuation of the tower and its twin got underway, television cameras broadcasted live images of what initially appeared to be a freak accident. Then, 18 minutes after the first plane hit, a second Boeing 767-United Airlines Flight 175-appeared out of the sky, turned sharply toward the World Trade Center and sliced into the south tower near the 60th floor. The US people cooperated with their government, strategies and wherewithal but the devastation that came in its wake is humongous and continues to inflict chaos and mayhem The collision caused a massive explosion that showered burning debris over surrounding buildings and onto the streets below. As millions watched the events unfolding in New York, American Airlines Flight 77 circled over downtown Washington, D.C., before crashing into the west side of the Pentagon military headquarters at 9:45 a.m. Jet fuel from the Boeing 757 caused a devastating inferno that led to the structural collapse of a portion of the giant concrete building, which is the headquarters of the U.S. Department of Defense. All told, 125 military personnel and civilians were killed in the Pentagon, along with all 64 people aboard the airliner. Meanwhile, a fourth California-bound plane-United Flight 93-was hijacked about 40 minutes after leaving Newark Liberty International Airport in New Jersey. The passengers fought the four hijackers and are suspected to have attacked the cockpit with a fire extinguisher. The plane then flipped over and sped toward the ground at upwards of 500 miles per hour, crashing in a rural field near Shanksville in western Pennsylvania at 10:10 a.m. All 44 people aboard were killed. Its intended target is not known, but theories include the White House, the U.S. Capitol, the Camp David presidential retreat in Maryland or one of several nuclear power plants along the eastern seaboard. A total of 2,996 people were killed in the 9/11 attacks, including the 19 terrorist hijackers aboard the four airplanes. 9/11 was a major calamity but what followed was even worse. The world had seen US retaliation after the attack on Pearl Harbour. The annihilation of Nagasaki and Hiroshima with nuclear weapons, which results in mutated children being born even today. In extreme anger, the US-led NATO forces combined to unleash their wrath on Afghanistan, the purported supporters of Osama bin Laden and his dreaded Al-Qaida. The massive firepower used against the Taliban and Al-Qaida decimated thousands of Afghans but the Taliban and Al-Qaida managed to survive, regroup and attack allied forces in Afghanistan. The US turned its attention on Iraq in 2003 and its full fury wreaked havoc on Mesopotamia. Closer to home, the war in Afghanistan trickled into Pakistan. A militant group by the name of Tehreek-e-Taliban Pakistan (TTP) was created, which targeted Pakistani Armed Forces and law enforcing agencies besides civilians because Pakistan was considered an ally of the US. The terror attacks in Pakistan claimed a toll of nearly 100,000 lives while billions of dollars’ worth of property was destroyed. When Pakistan turned its attention towards tackling the TTP, in retaliation, they targeted the innocent children studying at the Army Public School Peshawar. In a dastardly attack on December 16, 2014, one hundred and forty-two children were brutally slaughtered. This was a defining moment for Pakistan and some consider 12/16 to be Pakistan’s 9/11. The nation united in combating the scourge of terrorism. A National Action Plan (NAP) was evolved which sought to eliminate terror financing, extremism, hate speech and other aspects, which supported the miscreants. Military Operation Zarb-e-Azb followed by Radd-ul-Fasaad bore desired results. While the armed forces of Pakistan developed strategies to combat terrorism. They also designed software to locate terrorists from aerial platforms to seek and destroy them. Meanwhile, in the aftermath of 9/11, the US evolved new forces, organizations and strategies to ensure that a repeat of 9/11 does not occur. The US people cooperated with their government, strategies and wherewithal but the devastation that came in its wake is humongous and continues to inflict chaos and mayhem. Al-Qaeda gave way to a new monster in the shape of the Islamic State or Daesh. Though it has been defeated, it is not out and continues to threaten the peace of the region. The writer is a retired Group Captain of PAF. He is a columnist, analyst and TV talk show host, who has authored six books on current affairs, including three on China