Thousands of people have come together to mark one week since the Westminster attack, in which four victims and the attacker died.
Police officers, doctors and hundreds of members of a Muslim youth association were among those walking across Westminster Bridge in memory.
Leeds, Leicester, Sheffield, Manchester and Birmingham also had events.
Earlier, inquests into the victims’ deaths were opened and adjourned at Westminster Coroner’s Court.
Khalid Masood killed three people when he drove his hire car into pedestrians on Westminster Bridge last Wednesday.
Aysha Frade, 44, who worked at a London sixth-form college; US tourist Kurt Cochran, 54, from Utah; and retired window cleaner Leslie Rhodes, 75, from south London died.
After crashing, Masood then fatally stabbed PC Keith Palmer outside Parliament, before being shot dead by police.
In a statement, Ms Frade’s family said: “Our beloved Aysha; caring daughter, loving sister, amazing wife, irreplaceable aunt, thoughtful, supportive friend and the best and coolest of mummies.
“You were ripped away from our lives in the cruellest and most cowardly of ways. We now pray that you guide and protect not only us, but all of London, from further evil.
“You will always be remembered as our guardian angel who never shied away from facing up to bullies. There are no words to even begin to describe the crushing pain and eternal void left in our hearts.”
In Westminster on Wednesday, acting commissioner of the Metropolitan Police Craig Mackey said: “This afternoon is about remembering the victims of last week’s events.
“Our thoughts, our prayers, go out to everyone who was affected by the events last week.”
Zafir Malik, an imam from the Ahmadiyya Muslim Youth Association, said his members were “here to show that we are united with our fellow countrymen and remembering those who have fallen, especially PC Keith Palmer”.
As the vigil reached Parliament, dozens of people laid flowers on the side of the bridge, among them a man who was hurt in the attack.