Ambulances wait as members of the emergency services work on Westminster Bridge, alongside the Houses of Parliament in central London on March 22, 2017, during an emergency incident. British police shot a suspected attacker outside the Houses of Parliament in London on Wednesday after an officer was stabbed in what police said was a "terrorist" incident. One woman has died and others have "catastrophic" injuries following a suspected terror attack outside the British parliament, local media reported on Wednesday citing a junior doctor. / AFP PHOTO / NIKLAS HALLE'N (Photo credit should read NIKLAS HALLE'N/AFP/Getty Images)
Video Ad Feedback
London attack: Watch how it unfolded
Four people died and about 40 were injured when an attacker rammed a car into crowds of people before stabbing a police officer in the grounds of the UK Parliament in London.
1:26 • Source: CNN
Attack near British Parliament 15 videos
Ambulances wait as members of the emergency services work on Westminster Bridge, alongside the Houses of Parliament in central London on March 22, 2017, during an emergency incident. British police shot a suspected attacker outside the Houses of Parliament in London on Wednesday after an officer was stabbed in what police said was a "terrorist" incident. One woman has died and others have "catastrophic" injuries following a suspected terror attack outside the British parliament, local media reported on Wednesday citing a junior doctor. / AFP PHOTO / NIKLAS HALLE'N (Photo credit should read NIKLAS HALLE'N/AFP/Getty Images)
Video Ad Feedback
London attack: Watch how it unfolded
1:26
Now playing
• Source: CNN
khalid masood mughsot no bars
Video Ad Feedback
Neighbors describe London attacker
2:29
Now playing
• Source: CNN
london underground signs orig sg_00001502.jpg
Video Ad Feedback
London tube signs go viral after attack
0:45
Now playing
• Source: CNN
01 london attack vigil BANNER
Video Ad Feedback
Carrying on: The day after a terrorist attack
1:38
Now playing
• Source: CNN
london attack animated video map orig_00000000.jpg
Video Ad Feedback
London Attack: An animated map
0:55
Now playing
• Source: CNN
A picture shows red London buses, pedestrians and traffic crossing Westminster Bridge over the River Thames with the Union flag atop the Houses of Parliament (R) flying at half-mast in central London on March 23, 2017. Britain's parliament reopened on Thursday with a minute's silence in a gesture of defiance a day after an attacker sowed terror in the heart of Westminster, killing three people before being shot dead. Sombre-looking lawmakers in a packed House of Commons chamber bowed their heads and police officers also marked the silence standing outside the headquarters of London's Metropolitan Police nearby. / AFP PHOTO / Niklas HALLE'N (Photo credit should read NIKLAS HALLE'N/AFP/Getty Images)
Video Ad Feedback
London attack location: One thing to know
1:01
Now playing
• Source: CNN
Ambulances wait as members of the emergency services work on Westminster Bridge, alongside the Houses of Parliament in central London on March 22, 2017, during an emergency incident. British police shot a suspected attacker outside the Houses of Parliament in London on Wednesday after an officer was stabbed in what police said was a "terrorist" incident. One woman has died and others have "catastrophic" injuries following a suspected terror attack outside the British parliament, local media reported on Wednesday citing a junior doctor. / AFP PHOTO / NIKLAS HALLE'N (Photo credit should read NIKLAS HALLE'N/AFP/Getty Images)
Video Ad Feedback
Police name London attacker
1:28
Now playing
• Source: CNN
james cleverly
Video Ad Feedback
MP's emotional tribute to fallen officer
1:44
Now playing
• Source: CNN
Westminster bridge 4
Video Ad Feedback
A walk along where the London attack happened
2:28
Now playing
• Source: CNN
james cordon london attack 1
Video Ad Feedback
James Corden delivers emotional tribute
1:02
Now playing
• Source: CNN
Conservative Member of Parliament Tobias Ellwood, centre, helps emergency services attend to an injured person outside the Houses of Parliament, London, Wednesday, March 22, 2017. London police say they are treating a gun and knife incident at Britain's Parliament "as a terrorist incident until we know otherwise." The Metropolitan Police says in a statement that the incident is ongoing. It is urging people to stay away from the area. Officials say a man with a knife attacked a police officer at Parliament and was shot by officers. Nearby, witnesses say a vehicle struck several people on the Westminster Bridge. (Stefan Rousseau/PA via AP).
Video Ad Feedback
Amid London chaos, MP rushes to victim's aid
1:00
Now playing
• Source: CNN
sadiq khan cnn amanpour
Video Ad Feedback
Mayor: 'London is safest city in the world'
1:32
Now playing
• Source: CNN
British Prime Minister Theresa May speaks outside 10 Downing Street in central London on March 22, 2017, following the terror incident in Parliament earlier today. Britain will not change its terrorism threat level despite an attack in London on Wednesday which left three people and the assailant dead, Prime Minister Theresa May said. Three people were killed in a "terrorist" attack in the heart of London Wednesday when a man mowed down pedestrians on a bridge, then stabbed a police officer outside parliament before being shot dead. / AFP PHOTO / POOL / RICHARD POHLE (Photo credit should read RICHARD POHLE/AFP/Getty Images)
Video Ad Feedback
Theresa May: UK will never give in to terror
0:48
Now playing
• Source: CNN
Police and forensics officers investigate near buses abandoned on Westminster Bridge following a terror attack on March 22.
Video Ad Feedback
Witnesses describe 'horrendous' Parliament attack
1:23
Now playing
• Source: CNN
uk parliament stops gunshots sfc mobile orig_00000116.jpg
Video Ad Feedback
The moment the UK Parliament stopped
0:32
Now playing
• Source: CNN