Yet, amidst adversity and tragedy rose some likely and unlikely heroes.
In the precious moments before police could respond, it's these men and women who undoubtedly saved countless lives with their courageous actions.
How London stood up to knife attackers
Hero cop critically injured after rugby-tackling knifeman
An unidentified off-duty policeman was stabbed after he tackled one of the three attackers.
The officer, a rugby player, was among the first on the scene. He has sustained knife injuries and remains in critical condition.
London Metropolitan Police commissioner Cressida Dick has praised the "extraordinarily brave actions by officers on and off duty first on the scene" who "ran towards the danger."
Cop charged at attackers armed with just baton stick
A British Transport Police officer was left seriously injured after he charged at the attackers armed only with his baton. The officer, who has been with the BTP for just two years, is now in a stable condition. Police officials described his bravery as "outstanding."
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Off-duty nurse kept stabbing victim alive till paramedics arrived
One attacker had entered the El Pastor restaurant and stabbed a woman in the chest.
Diners started throwing chairs and bottles at the attacker and managed to push him out of the restaurant. Staff then lowered the security gates and locked everyone in.
33-year-old Carlos Pinto, a critical care nurse dining at the restaurant, kept the injured woman alive till paramedics reached two-hours later.
Teen thanks taxi driver for alerting her about knife attacker
19-year-old Rhiannon Owen, a student nurse, was at an ATM when a taxi driver shouted at her to run.
"I saw the knife and ... I just started running as fast as I could," Owen said.
Owen said she owed her life to the driver.
"You saved my life and you let me go and make sure other people were safe," she said.
London unites in aftermath of terror attack
After the attack, taxi drivers gave free rides to those stuck in the London Bridge area.
A plumber named Paul Ashworth cycled around the London Bridge area distributing cold water among police.
Ashworth said: "We've just to got to keep together - the whole world has."