Seven people have been killed and 48 people wounded - some critically - in an attack on London Bridge and the Borough Market area.
Saturday evening's events were captured in hundreds of videos and eyewitness accounts.
Shortly after 22:00 BST there were reports of a white van driving at 50mph (80kmh) along London Bridge, eyewitnesses said the van mounted the pavement and hit five or six people.
The van then crashed near the Barrowboy and Banker pub.
Eyewitness Eric saw three men get out of the white van. He said: "[They] ran towards the people that they nearly ran over.
"I thought oh maybe they're worried about them and trying to comfort them because obviously [I thought] it's an accident.
"[But] they literally just started kicking them, punching them, they took out knives and then they just, it was a rampage really.
"You could hear people screaming, they were getting stabbed."
The attackers then went into Borough Market, where they began stabbing people outside bars and restaurants.
An eyewitness, Gerard Vowls, 47, said: "They ran up and started stabbing this girl, three of them. I was defenceless, I couldn't do anything.
"They were running up going 'this is for Allah' and they stabbed this girl 10 or 15 times."
Gerard said he threw glasses, bottles, tables and chairs to try to stop them.
Speaking to BBC Radio 5 Live Richard - who was in a restaurant watching the attack unfold - said Gerard had done "a heroic thing", "putting our safety over his, which was remarkable".
Minutes after the first 999 call police swarmed the area.
James Yates posted a video of officers entering a basement bar on Southwark Street, where they told customers to "get down".
On the other side of Borough Market, Brendan was in the Wright Brothers restaurant with his girlfriend. He said: "All of a sudden there was a lot of commotion, within seconds it was obvious that something big was happening.
"I grabbed my girlfriend and hid behind the bar in the restaurant. We could hear gunfire and explosions.
"There were people running out of the bar across the road. Then a guy ran across the road up to me with a massive knife.
"He stared at me realising he wasn't getting in."
Photographer Gabriele Sciotto was in Borough Market at the time, and pictured a wounded suspect on the floor.
He said: "He's holding a bomb on the chest, he's bleeding from the left arm.
"The policeman you can see there in the picture was still pointing the gun at him."
Police have now said these belts were hoax devices.
Kumi de Costa was in a taxi while the attack was developing. She said: "The cab driver turned into the market and we got stuck right in the middle of the shooting. We were in a one-way street and couldn't turn around.
"There were loads of shots being fired. Two people were on the floor behind the church with two or three people leaning over them.
"A couple of times we had to lie down on the floor of the cab because of the shooting around us."
One couple heard screaming and running at Borough Market, but thought that it was a group of revellers.
But shortly afterwards they saw casualties.
"We ran, we saw some chefs in a smoking area behind a [hotel] and I came up to them and said 'there's been a terror attack, let's lock these doors and get people in [the hotel]," the man said.
Dozens of people were locked into the hotel and went up to the third floor. They stayed until an alarm went off and the hotel was evacuated.
Liam, who lives above the Southwark Tavern in Borough Market, told BBC Radio 5 Live, said: "I definitely heard this young guy try and get the attention of the ambulance saying 'my friend's been stabbed and he's in the pub'."
He also said that another man was walking around, covered in blood in a "dazed" state, asking the emergency services for help,
Tyson Oladokun, who was on London Bridge immediately after the attack, said: "I saw a man lying in the road being cradled by another man.
"I think I saw someone that had been stabbed and other people who I think had died."