From the left, British businessman Chris Norman, Anthony Sadler, a senior at Sacramento University in California, French President Francois Hollande, U.S. Airman Spencer Stone, and Alek Skarlatos a U.S. National Guardsman from Roseburg, Oregon pose at the Elysee Palace, Monday Aug.24, 2015 in Paris, France. Hollande pinned the Legion of Honor medal on U.S. Airman Spencer Stone, National Guardsman Alek Skarlatos, and their years-long friend Anthony Sadler, who subdued the gunman as he moved through the train with an assault rifle strapped to his bare chest. The British businessman, Chris Norman, also jumped into the fray. (AP Photo/Michel Euler, Pool)
Video Ad Feedback
Train heroes honored for thwarting attack
Four train passengers turned heroes received France's highest honor after foiling a terror attack. CNN's Nic Robertson has more from Paris.
2:08 • Source: CNN
Thwarted terror plots 15 videos
From the left, British businessman Chris Norman, Anthony Sadler, a senior at Sacramento University in California, French President Francois Hollande, U.S. Airman Spencer Stone, and Alek Skarlatos a U.S. National Guardsman from Roseburg, Oregon pose at the Elysee Palace, Monday Aug.24, 2015 in Paris, France. Hollande pinned the Legion of Honor medal on U.S. Airman Spencer Stone, National Guardsman Alek Skarlatos, and their years-long friend Anthony Sadler, who subdued the gunman as he moved through the train with an assault rifle strapped to his bare chest. The British businessman, Chris Norman, also jumped into the fray. (AP Photo/Michel Euler, Pool)
Video Ad Feedback
Train heroes honored for thwarting attack
2:08
Now playing
• Source: CNN
us attorney ohio terror attack thwarted 2
Video Ad Feedback
Man accused of plotting attack at parade
1:45
Now playing
• Source: WJW
Armed police operate in Saint-Denis, a northern suburb of Paris, Wednesday, Nov. 18, 2015. Police say two suspects in last week's Paris attacks, a man and a woman, have been killed in a police operation north of the capital. Two police officers have been injured in the standoff. Police have said the operation is targeting the suspected mastermind of last week's attacks, believed to be holed up in an apartment in Saint-Denis with several other heavily armed suspects. (AP Photo/Francois Mori)
Video Ad Feedback
What to do in the event of a terror attack
1:42
Now playing
• Source: CNN
psychology of terror sanjay gupta nws orig_00002811.jpg
Video Ad Feedback
The psychology of terror
1:25
Now playing
• Source: CNN
LAS VEGAS, NV - OCTOBER 02: An ambulance leaves the intersection of Las Vegas Boulevard and Tropicana Ave. after a mass shooting at a country music festival nearby on October 2, 2017 in Las Vegas, Nevada. A gunman has opened fire on a music festival in Las Vegas, leaving at least 20 people dead and more than 100 injured. Police have confirmed that one suspect has been shot. The investigation is ongoing. (Photo by Ethan Miller/Getty Images)
Video Ad Feedback
When is something 'terrorism'?
2:46
Now playing
• Source: CNN
australia terror plot cabrera kayyem segment_00002218.jpg
Video Ad Feedback
Four arrested in alleged airplane terror plot
1:39
Now playing
• Source: CNN
Washington, UNITED STATES: The terrorist threat advisory is seen 10 August, 2006 at Ronald Reagan National Airport, in Washington, DC. After Britain said 10 August it had thwarted a plot to wreak "mass murder" by the simultaneous mid-air bombings of planes to the United States, the US raised the threat level to "severe" or "Red" for all commercial flights flying from Britain to the United States, and "high" or "Orange" for all commercial aviation operating in the United States, including international flights. AFP PHOTO / TIM SLOAN (Photo credit should read TIM SLOAN/AFP/Getty Images)
Video Ad Feedback
What FBI director wants Americans to know about terror
1:11
Now playing
• Source: CNN
Investigators inspect a truck following a shooting incident in New York on October 31, 2017. Several people were killed and numerous others injured in New York on Tuesday when a suspect plowed a vehicle into a bike and pedestrian path in Lower Manhattan, and struck another vehicle on Halloween, police said. A suspect exited the vehicle holding up fake guns, before being shot by police and taken into custody, officers said. The motive was not immediately apparent. / AFP PHOTO / Don EMMERT (Photo credit should read DON EMMERT/AFP/Getty Images)
Video Ad Feedback
The vulnerability of 'soft targets' to terror
1:43
Now playing
• Source: CNN
The operations center of the Terrorist Screening Center
Video Ad Feedback
An exclusive look inside the Terrorist Screening Center
5:20
Now playing
• Source: CNN
handgun STOCK
Video Ad Feedback
Is this terror or a mass killing?
1:56
Now playing
• Source: CNN
terror attack vulnerabilities brown dnt tsr_00013715.jpg
Video Ad Feedback
How vulnerable are citizens to terror attacks?
1:41
Now playing
• Source: CNN
In this photo provided by Christina Cathleen Coons, a person lies on the floor after an incident on a high-speed train traveling from Amsterdam to Paris on Friday, Aug. 21, 2015. A gunman opened fire on the train wounding several people before American passengers subdued him, according to officials and one of the Americans involved. (Christina Cathleen Coon via AP)
Video Ad Feedback
Exclusive cell phone video from inside train
1:04
Now playing
• Source: Anthony Sadler
tsr dnt scuitto ISIS plots thwarted_00005604.jpg
Video Ad Feedback
FBI: Several July 4th terror attacks thwarted
1:41
Now playing
• Source: CNN
isis in america north carolina teen arrested sciutto dnt tsr _00001312.jpg
Video Ad Feedback
American teen arrested in alleged ISIS plot
1:43
Now playing
• Source: CNN
03 boston police shooting
Video Ad Feedback
New details released in Boston terror plot
2:12
Now playing
• Source: CNN