There were you on September 11, 2001? In the United States, “9-11-01” is a date that few will ever forget as the world literally stopped turning as terrorists threatened our nation’s safety and took thousands of innocent lives. While the attack on American soil has created a heightened awareness of other attacks, there are dozens of attacks throughout history that have rattled communities around the world that many may not remember.

Defined by the element of surprise and typically associated with religious and political opinions, terrorist attacks don’t discriminate when it comes to location or method. From car bombs and burnings to school sieges, hostage crises and airplane hijackings, terrorists have taken thousands of lives everywhere from small villages in Nigeria and Algeria to bustling cities like Moscow and Oklahoma City.

So, out of all of the documented terrorist attacks throughout world history, which stand out as the most tragic and horrific? What were the motives of the terrorists, how many lives were taken and how many others were injured? It’s time to get the answers as we take a look at 20 of the most terrifying terrorist attacks that have been documented around the world.

#21 - Baga massacre 2015 

The 2015 Baga massacre was a series of mass killings carried out by the jihadist group Boko Haram in the Nigerian town of Baga and its environs, in the state of Borno, between 3 January and 7 January 2015.

The attack began on 3 January when Boko Haram overran a military base that was the headquarters of the Multinational Joint Task Force containing troops from Chad, Niger, and Nigeria. The militants then forced thousands of locals from the region and committed mass killings that culminated on the 7th.
Fatalities have been reported to be "heavy" but their extent is unclear. Several western media reported that "over 2,000" people are thought to have been killed or "unaccounted for", but local media reported "at least a hundred" fatalities, while the Nigerian Ministry of Defence said that no more than 150 people in total had been killed, including militants.Several government officials denied that the fatalities were as extensive as reported, with some even claiming that the massacre had never taken place or that the Nigerian military had repelled the militants from the region, a claim that was refuted by local officials, survivors, and the international medi

#20 – Massacre of Trujillo

While most terrorist attacks take place in a matter of hours, minutes or even seconds, the Massacre of Trujillo in southwestern Columbia occurred over a span of six years. Taking place between 1988 and 1994, the town of Trujillo was targeted by paramilitaries and the Cali Cartel who tortured, murdered and dismembered anywhere from 245 to 342 people as local police officers and the Columbian military watched.

Recognized in Columbia as one of the most gruesome murdering sprees in history, the Massacre was all done in the name of warning and putting an end to guerrilla supporters and unionists. With even the local Jesuit priest murdered and castrated, the victims never received a ceremonious burial as their bodies were tossed aside to litter the waters of the local Cauca River. Despite the Columbian government admitting their guilt in not preventing such horrific crimes, no one was ever brought to justice for the deaths of so many innocent men, women and children.

#19 – Moscow Theater Hostage Crisis

Also known as the 2002 Nord-Ost siege, the Moscow Theater Hostage crisis was yet another chapter in the longstanding conflict between Chechnya and Russia. Occurring on October 23, 2002, Chechen military leader Movsar Barayev led around 40 Chechens who were part of the Islamist military separatist movement as they sieged the crowded Dubrovka Theater. Taking 850 hostages, the Chehens demanded that Russia withdraw from the region and end the war.

Over a span of two-and-a-half days, tensions ran high after two female hostages were executed and a series of explosives rigged inside the theater threatened massive casualties. The standoff finally came to an end when Russian authorities pumped a chemical agent into the theater’s ventilation system killing all 40 of the attackers and 130 hostages. With hundreds more left injured, Russia’s decision to use a nondisclosed chemical agent to end the crisis was met with widespread criticism as many believed more lives could have been saved.

#18 – Oklahoma City Bombing

On April 19, 1995, Americans stood together in shock and terror as the Alfred P. Murrah Federal Building in Oklahoma City crumbled to the ground killing 168 people, injuring nearly 700 others and damaging hundreds of structures in a 16-block radius. Carried out by Timothy McVeigh and Terry Nichols, the bombing was McVeigh’s retaliation against the federal government for how they handled the siege on Waco, Texas exactly two years prior (to the minute) in 1993.

Causing over $650 million worth of damage, McVeigh fled the scene only to be caught an hour and a half later by an Oklahoma State Trooper for driving without a license plate. Arrested for possessing illegal weapons, McVeigh was quickly linked to the attack. With the bombing as the deadliest domestic terrorist attack in the United States, McVeigh was sentenced to death row in Terre Haute, Indiana where he died by lethal injection on June 11, 2001.

#17 – 1998 U.S. Embassy Bombings

Three years after the Oklahoma City Bombing, the United States was attacked once again on foreign soil at the United States Embassy in Dar es Salaam, Tanzania and Nairobi, Kenya. On August 7, 1998, over 200 people were killed at the Embassy as a result of an attack orchestrated by Egyptian Islamic Jihad members inspired by Ayman al-Zwahiri and Osama bin Laden, who came to America’s attention for the first time and landed a spot on the FBI’s list of most-wanted fugitives.

Carried out by truck bombs loaded with TNT, ammonium nitrate, guns and stun grenades, the attacks left over 4,000 people injured who required treatment at the scenes and at local hospitals. The United States responded to the attacks when President Bill Clinton ordered Operation Infinite Reach which saw the launch of cruise missile strikes set for specific targets in both Sudan and Afghanistan. With Nairobi’s Embassy having to be rebuilt, America reaffirmed their commitment to fighting terrorism in Kenya and launched even greater efforts to provide financial assistance.

#16 – Metrojet Flight 9268

One of the most recent terrorist attacks on our list and the freshest on our minds, the Metrojet Flight 9268 mysteriously crashed on October 31, 2015. Carrying 217 passengers and 7 crew members, the Airbus A321-231 disintegrated in the air over Sinai while in route between the Sharm el-Sheikh International Airport in Egypt and the Pulkovo Airport in Russia. With a death toll of 224 people, the crash became the deadliest in Russian aviation history.

Leaving many confused as to how the plane disintegrated in mid-flight, ISIS quickly claimed responsibility for the attack and said that they planted a bomb onboard the flight that was carrying 219 Russians, four Ukrainians and a Belarusian. Days later, investigators confirmed that a bomb brought down the plane with the Russian government also releasing a statement in the weeks that followed confirming that they were positive the crash was a terrorist attack as a result of TNT explosive residue that had been discovered on plane debris.

#15 – 2001 Angola Train Attack

Lasting over 26 years from its start on November 11, 1975 to its end on April 4, 2002, the Angolan Civil War created massive bloodshed for the country. The war, however, culminated on August 10, 2001 when a terrorist attack claimed the lives of 252 people and injured over 160 others as members of the UNITA (National Union for the Total Independence of Angola) rebels derailed a train traveling between the towns of Zenza and Dondo.

Using a tank-mine to derail and crash the train, the UNITA rebels forced their way on board and opened fire on the train’s 500 passengers, taking a total of 250 lives in the process. In the aftermath of the incident, many believed the event was part of the war but when UNITA claimed responsibility three days later, the United Nations Security Council deemed it a terrorist attack. Months later, the People’s Movement for the Liberation of Angola claimed their victory and ended the 26-year civil war.

#14 – 1993 Bombay Bombings

Much like Kenya and Angola, India has also been the target of terrorist attacks with the largest and most destructive bombings in the country’s history occurring on March 12, 1993 in the city of Bombay. Coordinated by Mumbai-based mafia groups led by Dawood Ibrahim, a series of 13 bombs were detonated by Ibrahim’s subordinates, Tiger and Yakub Memon, and claimed the lives of 257 innocent bystanders and injured 717 others.

Leading an organized crime group known as the D-Company, Ibrahim and his followers were financially supported by several other prominent smugglers making their escape easy to pull off. As a result, Ibrahim, Tiger Memon and numerous others who helped orchestrate the attack have yet to be arrested or charged for their crimes. As for Tiger’s brother, Yakub was finally caught and sentenced for execution which occurred on July 30, 2015.

#13 – Pan Am Flight 103

The second flight on our list, Pan Am Flight 103 was scheduled to leave Frankfurt, Germany on December 21, 1988 with stops in London and New York City before making its final landing in Detroit, Michigan. Unfortunately, the flight never made it that far as it crashed over Galloway, Scotland when a bomb destroyed the flight in air, killing all 243 passengers and 16 crew members in addition to 11 other people on the ground.

After a three-year investigation with FBI and Scotland officials, it was determined that the Boeing 747 was bombed by a Libyan group as arrest warrants were issued for two nationalists who claimed their involvement. In 1999, Libyan leader Colonel Muammar Gaddafi turned the two men over to the Netherlands for the trial. The only person ever convicted, however, was Abdelbaset al-Megrahi who was jailed for life on 270 counts of murder and served eight years before being granted a compassionate release after being diagnosed with prostate cancer. He continued to argue his innocence until his death in 2012.

#12 – Russian Apartment Bombings

Russia suffered yet another devastating terrorist attack in 1999 when a series of bombings between September 4th and September 16th killed 300 people and injured over one thousand others. Detonated across four apartment blocks in the cities of Buynaksk on September 4th, Moscow on September 9th and 13th, and Volgodonsk on September 16th, the bombings became what many Russians believed as the launch of the Second Chechen War.

With the official Russian investigation of the bombings completed in 2002, authorities believe that the attacks were orchestrated by Achemez Gochiyaev who has yet to be brought in for questioning. As a result, many Chechen authorities and Russian critics believe that the bombings were a false ploy that allowed Russia to initiate a second full-scale war with Chechnya to bring Russian Prime Minister Vladimir Putin to even greater power.

#11 – 1983 Beirut Barracks Bombing

Yet another terrorist attack occurring in the midst of a civil war, the 1983 Beirut Barracks Bombings took place during the Lebanese Civil War which lasted from 1975 until 1990. Occurring on October 23, 1983, a virtually unknown Islamic Jihad group orchestrated an attack in which a pair of truck bombs driven by suicide bombers brought down two barracks buildings housing military members from the United States and France. As a result of the attacks, 241 American soldiers, 58 French paratroopers and 6 civilians were killed.

With Iran, Syria and Hezbollah continuing to deny their involvement even today, the attacks ultimately led to the withdrawal of all international peacekeeping efforts in Lebanon. In 2001, a civil suit occurred as family members of the service men who lost their lives took the Islamic Republic of Iran to court. A default was entered and the families were awarded over $2.6 billion for the devastating tragedy.

#10 – Air India Flight 182

The third of four airline related tourist attacks on our list, Air India Flight 182 was destroyed by a bomb on June 23, 1985. Operating its normal route between Montreal, London and Delhi, the Boeing 747 was at an altitude of 31,000 feet when a bomb was detonated causing it to plummet from Irish airspace into the Atlantic Ocean killing 307 passengers and 22 crew members for a death toll of 329.

With the majority of victims being Canadian citizens, the crash became the largest mass murder in Canadian history and was the deadliest air-based terrorist attack in the world until September 11, 2001. Occurring at the same time as the Narita International Airport Bombing in Tokyo, investigators believe that the attacks were linked and that those responsible were members of a Sikh militant group known as Babbar Khlasa who were retaliating against India for Operation Blue Star, which took place in 1984.

#9 – Beslan School Hostage Crisis

Terrorist attacks are already tragic enough but, when they involve innocent children like the 2004 Beslan School Hostage Crisis, they are even more terrifying. On September 1, 2004, Islamic terrorists from Chechnya forced their way into School Number One in the town of Beslan, Russia. Taking over 1,100 hostages including nearly 800 children, the terrorists demanded recognition of Chechnya’s independence as well as Russia’s withdrawal from their country.

With the standoff lasting for three days, Russian security forces were finally able to advance on the building on September 3, 2004 using tanks, rockets and other heavy weaponry. Becoming known as a massacre with a death toll of 186 children and over 200 adults, the effects of the standoff are still felt today as many believe there is more to the story than what the local media reported. Russia has even faced criticism on how they responded to the attacks leaving many to argue that their use of excessive force was completely unnecessary.

#8 – Bentalha and Rais Massacre

While small villages are often not the targets of terrorist attacks, this unfortunately wasn’t the case for the Algerian villages of Bentalha and Rais who saw tragedy firsthand in 1997 at the height of civil unrest throughout the country. The village of Rais was attacked by hooded terrorists armed with guns, knives, bombs and axes on August 29th in what would become one of the bloodiest massacres in Algeria in the 1990s with death toll reports ranging anywhere from 100 to 800 villagers.

Nearly a month later on the night of September 22nd and in the early hours of September 23rd, armed guerillas attacked the village of Bentalha when they went from house to house and killed men, women and children inside. With death toll reports varying between 85 and 400, both the Bentalha and Rais Massacres were motivated by the cancelation of the 1992 election that was set for an Islamic Salvation Front victory. Villages like Rais and Bentalha who cut off the guerillas from supplies found themselves as targets during the bloodshed of 1997.

#7 – Munich Massacre

When it comes to high profile athletic events like the Super Bowl, the World Series or something as big as the Olympics, heightened security has become a standard especially after the 1972 Summer Olympic Games in Munich, Germany. With Munich as part of West Germany at the time, 11 members of the Israeli Olympic team were in the Olympic Village when they were taken hostage by a Palestinian extremist group known as Black September who demanded 234 Palestinian prisoners in Israel and the founders of the Red Army Faction be released. ‘

With assistance from German neo-Nazis, the group of eight terrorists held the hostages for nearly 24 hours before the tragedy came to a sad and bloody end as the world watched on live television. After several failed rescue attempts by German police, Black September members opened fire on the Israeli team killing 6 coaches and 5 athletes. As a gun battle erupted between the terrorists and local authorities, five members of Black September were killed in addition to one West German police officer.

#6 – Gamboru 2014 Attack

Another recent attack on our list, the twin Nigerian towns of Gamboru and Ngala were brought to rubble on the night of May 5, 2014. Orchestrated by an Islamic extremist group out of northern Nigeria known as Boko Haram, the terrorists killed over 300 residents and left the few remaining survivors no other choice but to desert their town and flee to the neighboring village of Cameroon.

Abducting 11 young girls between the ages of 12 and 15 in northeast Nigeria on the same night, the Boko Haram militants were set for destruction as they stormed the unsuspecting towns in two armored vehicles carrying AK-47 assault rifles and rocket propelled grenade launchers that they had stolen from the Nigerian military. Opening fire in a busy night market and setting homes ablaze, militants brutally gunned down anyone who tried to escape the burning and devastating wrath.

#5 – Paris 2015 Attack

Traveling from Nigeria to France, the November 13, 2015 attacks on Paris are the most recent terrorist attacks on our list. In a series of suicide bombings, shootings and hostage situations, the City of Lights and its northern suburb of Saint-Denis were devastated as 130 people were killed and nearly 400 others were injured with the most casualties occurring at the Bataclan Theatre when ISIS members opened fire on the audience.

Bombings shut down city traffic, buildings were on strict lockdown and the nearby stadium filled with soccer players and fans was under high alert as the Paris attacks became the deadliest seen in France since the second World War. As ISIS openly took responsibility for the attack as retaliation on France for their attacks on members in Syria and Iraq, Francoise Hollande said that the Paris attacks were an act of war by ISS that would never be forgotten or forgiven.

#4 – Cinema Rex Fire

One of the most horrifying aspects of terrorism is the feeling of being trapped, which is exactly what happened to nearly 500 people inside the Rex Cinema on August 19, 1978 in Abadan, Iran. As moviegoers sat in their seats enthralled by the latest films, terrorists barred the doors, doused the entire building in gasoline and set it ablaze leaving those inside with no way to escape alive.

With conflicting reports around the death toll ranging anywhere between 400 and 800, there was also widespread speculation over who was responsible for the attacks. The Iran government ruled that Islamic militants were to blame for the Rex Cinema fire while protestors argued that Iran’s national intelligence service known as SAVAK orchestrated the entire event. Once confirmed that the militants were guilty, five of them were put to death including the man who started the fire, Hossein Takbalizadeh.

#3 – 1990 Sri Lanka Police Massacre

Day in and day out police officers around the world risk their lives for the safety of others but, on June 11, 1990, Sri Lankan police officers suffered the unthinkable when they were unable to protect even themselves. In the early morning hours of June 11th, around 250 members of the Liberation Tigers of Tamil Eelam invaded the Batticaloa police station and ordered surrounding stations to evacuate as they took millions in cash, jewelry and weapons before abducting the officers and holding them hostage at the airport and nearby church.

Far from finished wreaking havoc on the province, the militants abducted nearly 900 more officers before unarming them, taking their valuables, binding their hands and executing them. Leaving anywhere from 600 to 800 officers dead, the terrorist attacks launched the second of four Eelam Wars that have left many innocent people dead as a result of the growing hatred between the Sri Lankan military and the Liberation Tigers.

#2 – Yazidi Communities Bombings

From the beginning of the Iraq War in March 2003 to its end in December 2011, car bomb attacks became some of the most notorious strikes of the enemy. The deadliest of these attacks came on the evening of August 14, 2007 when 500 people were killed and 1,500 others were injured as four car bombs were simultaneously detonated in the towns of Kahtaniya and Jazeera leaving the American government to believe that Al-Qaeda members were to blame.

The August attacks targeted the Yazidi people, a religious minority group in Iraq who had been receiving threatening letters warning them of an impending attack for several months prior. As the threats proved true, two tons of explosives crumbled neighborhoods and city buildings leaving entire families buried under the rubble. Rescue efforts saved many but left hospitals and pharmacies without food, water and medicine, which made the catastrophe a complete devastation for the villages.

#1 – September 11th

The most horrifying terrorist attack on our list is not only one that forever changed the world, but is one that no one in the United States will ever forget. Taking place on the morning of September 11, 2001, four commercial airliners were hijacked shortly after departing from the East Coast. One plane crashed into a field near Shanksville, Pennsylvania as passengers overcame the attackers while another plane hit the Pentagon in Washington, D.C. The other two planes crashed into the twin towers of the World Trade Center in New York City.

With 2,996 people killed and 6,000 others injured from the debris that fell onto the streets of New York City as well as the rescue efforts in the months that followed, the September 11th attacks were the mastermind of al-Qaeda who sent 19 militants to hijack the planes. Launching the War on Terror, the American military invaded Afghanistan as al-Qaeda leader, Osama bin Laden, finally took responsibility for the attacks in 2004. Evading capture for nearly a decade, the United States military finally located and killed bin Laden in May 2011.