On September 11, 2001, the world witnessed a terrorist attack on a scale never seen before. Four passenger planes were hijacked by Al-Qaeda terrorists: two crashed into the towers of the World Trade Center in New York, another into the Pentagon, and the fourth crashed in Pennsylvania after passengers attempted to regain control of the aircraft. As a result, 2,977 people from 90 countries were killed. Twenty-five years later, September 11 remains the deadliest terrorist attack in modern history.
Its consequences proved to be far greater than the destruction in New York and Washington. The U.S. launched a global “war on terror,” invaded Afghanistan, overhauled the operations of its intelligence agencies and aviation security, and many procedures that now seem routine at airports were introduced or significantly tightened after 2001.
But September 11 is far from the only attack that claimed hundreds of lives. Over the past decades, terrorists have blown up passenger planes, trucks in city centers, hotels, restaurants, embassies, and religious sites.
UA News looks at the deadliest terrorist attacks in modern history and how security measures around the world have changed in their wake.
September 11, 2001, claimed 2,977 lives and remains the deadliest terrorist attack in history
On the morning of September 11, 2001, 19 Al-Qaeda terrorists hijacked four passenger planes operating domestic flights within the United States.
At 8:46 a.m., American Airlines Flight 11 crashed into the North Tower of the World Trade Center. At first, it wasn’t even clear whether this was a deliberate attack. But 17 minutes later, United Airlines Flight 175 crashed into the South Tower.
After the second crash, there was no longer any doubt. Another hijacked plane, American Airlines Flight 77, crashed into the Pentagon. The fourth—United Airlines Flight 93—did not reach its target. Passengers, who had learned of the attacks in New York by phone, attempted to regain control of the plane. It crashed in a field in Pennsylvania.
According to the National September 11 Memorial & Museum, 2,977 people died: 2,753 in New York, 184 at the Pentagon, and 40 passengers and crew members on Flight 93. Among the dead were hundreds of firefighters, police officers, and first responders.
The FBI calls September 11 the deadliest terrorist attack in history. The investigation, codenamed PENTTBOM, became the largest in the bureau’s history: at its peak, more than half of all FBI agents were assigned to the case.
But the main legacy of the attacks was not just the numbers. The U.S. created the Department of Homeland Security, significantly expanded the capabilities of intelligence and counterterrorism agencies, changed the rules for screening passengers and luggage, and strengthened cockpit security.
September 11 effectively changed nations’ perceptions of what terrorism could be. An airplane, which until then had been primarily a means of transportation, was transformed into a weapon in a matter of hours.
The 2017 explosion in Mogadishu claimed at least 587 lives and became the deadliest in Africa
On October 14, 2017, a truck packed with explosives detonated in the center of Mogadishu, the capital of Somalia. The location of the attack was chosen to maximize the impact. The truck exploded at one of the city’s busiest intersections, near hotels, shops, restaurants, and government buildings.
A fuel tanker was nearby, which further intensified the explosion and the fire. Initial reports indicated dozens of fatalities. The death toll then began to rise rapidly as more victims were found under the rubble, and some of the bodies were difficult to identify.
According to more definitive UN data, at least 587 people were killed. Hundreds were injured. The United Nations called the attack the deadliest terrorist bombing involving an improvised explosive device in African history.
At that time, Somalia had already been fighting the Islamist group al-Shabaab, linked to al-Qaeda, for many years. It was this group that was blamed for most of the major attacks in the country.
The attack in Mogadishu also highlighted a very simple yet terrifying aspect of modern terrorism: to cause a massive number of casualties, it is not necessary to have sophisticated weapons or hijack airplanes.
All it takes is a large amount of explosives, a truck, and a crowded city street. This is precisely why such attacks using vehicles laden with explosives have become one of the greatest challenges to urban security in countries where terrorist organizations operate.
The 1985 Air India Flight 182 bombing killed 329 people and became the deadliest terrorist attack in Canadian history
On June 23, 1985, an Air India Boeing 747 was flying from Canada to India via London. While the plane was flying over the Atlantic Ocean off the coast of Ireland, a bomb exploded in the cargo hold.
The plane broke apart in midair. All 329 passengers and crew members were killed. Most of them were Canadian citizens, and more than 80 children were among the victims. To this day, the Canadian government calls the destruction of Air India Flight 182 the largest terrorist attack in the country’s history.
The investigation determined that the crash was caused by a bomb planted in the luggage. The attack was linked to Sikh extremists operating in Canada. On the same day, another bomb—intended for a different Air India flight—exploded at Narita Airport in Japan, killing two employees.
The disaster became one of the main arguments in favor of significantly stricter baggage screening. Prior to this, under certain conditions, a suitcase could end up on board even without its owner. After a series of aviation terrorist attacks, this approach began to change.
Air India Flight 182 highlighted yet another problem: international terrorism can be organized in one country, directed against another, while the attack itself takes place thousands of kilometers away from both.
The 1988 Lockerbie bombing claimed 270 lives and became one of the most notorious aviation terrorist attacks of the 20th century
On December 21, 1988, Pan Am Flight 103 departed London for New York. Less than 40 minutes after takeoff, the Boeing 747 exploded in the sky over the Scottish town of Lockerbie.
All 259 people on board were killed. Debris from the plane fell on residential neighborhoods in the town, killing another 11 people on the ground. The total number of victims was 270.
The FBI calls the Pan Am 103 explosion one of the largest acts of international terrorism the bureau has ever investigated. Until September 11, it was the deadliest terrorist attack against Americans.
The scale of the investigation was enormous. Debris from the Boeing was scattered over an area of more than 800 square miles. Investigators had to literally piece the plane back together to determine the location of the explosion and the bomb’s design.
The U.S. investigation linked the attack to members of Libyan intelligence. A decade later, the Lockerbie case remains unresolved: legal proceedings continue in the U.S. against individuals suspected of involvement in the manufacture of the explosive device.
The 2019 Easter attacks in Sri Lanka claimed 258 lives in a single morning
On April 21, 2019, Easter Sunday, Sri Lanka experienced a series of nearly simultaneous explosions. Terrorists attacked Christian churches and luxury hotels in several cities.
The timing was no coincidence. Easter services were being held in the churches, while local residents and foreign tourists were having breakfast at the hotels. One of the hardest-hit sites was St. Sebastian’s Church in Negombo.
According to the UN Security Council, 258 people were killed at seven locations in three cities. The attacks were carried out by suicide bombers from the local radical groups National Thowheed Jamath and Jammiyathul Millathu Ibrahim. According to the UN, some of the attackers had previously traveled to Syria and undergone training there, and they used ISIS methods when constructing the explosive devices.
It was this coordination that made the attacks particularly dangerous. Several explosions occurred almost simultaneously, forcing police and medical personnel to respond to multiple major incident sites at once.
Following the attacks, questions arose regarding the work of the intelligence agencies: information about a possible threat had been received even before the attacks, but it was not properly acted upon. Thus, one of the country’s greatest tragedies also served as an example of just how costly the disconnect between intelligence received and the state’s actual response can be.
The bombings near U.S. embassies in Africa in 1998 claimed 224 lives and propelled al-Qaeda onto the world stage
On August 7, 1998, car bombs exploded almost simultaneously near the U.S. embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania. A total of 224 people were killed, including 12 Americans. More than 4,500 others were injured.
According to the FBI, the attacks were carried out by members of al-Qaeda.
Nairobi suffered the most damage. The explosion occurred in a densely populated part of the city, so many of the victims had no connection whatsoever to the U.S. embassy. For the United States, these attacks served as one of the main warnings of the growth of Osama bin Laden’s international network.
Until 1998, his name was known mainly to intelligence agencies and those who monitored international terrorism. After the bombings in Kenya and Tanzania, al-Qaeda became a global problem.
Three years later, this same organization would carry out the September 11 attacks.
The explosion of Metrojet Flight 9268 over the Sinai Peninsula in 2015 killed all 224 people on board
On October 31, 2015, a Metrojet Airbus A321 took off from Sharm el-Sheikh, Egypt, bound for St. Petersburg. There were 217 passengers and seven crew members on board.
About half an hour after takeoff, the plane disappeared from radar and crashed on the Sinai Peninsula. All 224 people on board were killed. The Sinai branch of ISIS claimed responsibility for the crash. Russian investigators later stated that an explosive device had detonated on board.
The attack had a massive impact on Egypt’s tourism industry. A number of countries temporarily suspended or restricted flights to Sharm el-Sheikh, and special attention was once again focused on screening not only passengers but also airport staff and access to aircraft on the ground.
Thirty years after the Air India bombing, the world was once again reminded that aircraft security begins long before a plane takes to the air.
The 2002 Bali bombings claimed 202 lives and demonstrated just how vulnerable tourist destinations are
On October 12, 2002, explosions rocked the tourist district of Kuta on the Indonesian island of Bali. One of the main targets was the Sari Club nightclub, where a large number of tourists were present.
As a result, 202 people from various countries around the world were killed. Hundreds were injured and suffered burns. The Australian Department of Foreign Affairs and Trade confirmed the total death toll of 202. The attack was linked to the radical group Jemaah Islamiyah, which had ties to al-Qaeda.
Bali was of immense importance to the tourism industry. After September 11, the world’s attention was focused on airplanes, airports, and government buildings. But Bali showed that places without heavy security—yet where hundreds of people from dozens of different countries gather at the same time—can also be ideal targets.
Afterward, many tourist destinations in Asia began taking vehicle inspections, hotel security, and access controls to popular tourist spots much more seriously.
The 2008 Mumbai attacks lasted nearly three days and turned the metropolis into a battlefield
On November 26, 2008, ten militants arrived in Mumbai by sea. After disembarking, they split into groups and simultaneously attacked several locations. Among them were the Chhatrapati Shivaji Terminus train station, restaurants, the Nariman House Jewish center, and two large hotels—the Oberoi Trident and the famous Taj Mahal Palace.
Unlike many other terrorist attacks, there was no single large explosion here. The attackers roamed the city armed with small arms and grenades, shooting people and taking hostages.
The operation to neutralize the terrorists lasted nearly three days. According to the U.S. Department of Justice, 166 people were killed and hundreds were wounded. Nine out of ten attackers were killed.
Mumbai became particularly significant for intelligence agencies because of the very nature of the attack. The terrorists did not need a single super-powerful bomb. Small armed groups were able to simultaneously create dozens of crisis situations in different parts of a city with a population of several million.
After Mumbai, the scenario of a so-called “multi-site attack”—a coordinated attack on multiple targets—began to be taken much more seriously in the training of police and special forces in various countries.
The 1995 Oklahoma City bombing demonstrated that terrorists can be citizens of the very country they are attacking
On April 19, 1995, a rented truck exploded near the Alfred P. Murrah Federal Building in Oklahoma City. The blast virtually destroyed part of the nine-story building.
One hundred sixty-eight people were killed, including 19 children. Hundreds were injured, and more than 300 surrounding buildings were damaged or destroyed. The FBI calls the attack the deadliest act of domestic terrorism in U.S. history.
The perpetrator was Timothy McVeigh, an American and U.S. Army veteran with radical anti-government views. This was of fundamental importance. After previous attacks, many Americans had come to view terrorism primarily as an external threat. Oklahoma City demonstrated that a large-scale terrorist attack could be carried out by radicalized citizens of the country itself.
After every major terrorist attack, the world patched up an old vulnerability, but terrorists found a new one
If we look at these attacks collectively, a pattern emerges. After the Air India and Lockerbie attacks, governments tightened security checks on luggage and explosives at airports. After Oklahoma City, more attention began to be paid to domestic extremism and the protection of government facilities.
After the bombings of U.S. embassies, the focus shifted to protecting diplomatic facilities. After 9/11, the entire global aviation security system was effectively overhauled. After Bali and Sri Lanka, it became clear just how vulnerable hotels, religious sites, and tourist areas could be.
After Mumbai, law enforcement agencies began to prepare more actively for a scenario in which several small groups simultaneously attack different parts of a large city. And Mogadishu demonstrated once again that even a relatively simple truck bomb can claim hundreds of lives if terrorists choose the right place and the right moment.
That is why, 25 years later, the consequences of September 11 can be seen far beyond the memorial in New York. They are evident in airport scanners, locked cockpit doors, concrete barriers around government buildings, vehicle checks outside hotels, security at large concerts, and in the way intelligence agencies from different countries share information.
But the history of other attacks shows something else: after every new security measure, terrorists have tried to find a way to circumvent it. That is precisely why the fight against terrorism almost never ends after the arrest of specific perpetrators. It turns into a constant race between new methods of attack and new ways to prevent them.
