The book of condolence at London's City Hall was opened amid complete silence.
Not one word was uttered by politicians, Underground staff, faith and community leaders as they stepped forward to sign.
Mayor Livingstone called for tolerance in his message
Against the backdrop of a city busily getting back to work, each paid silent tribute to the victims of Thursday's bombings.
First to sign was London mayor Ken Livingstone, who wrote: "The city will endure - it is the future of our world. Tolerance and change."
Culture Secretary Tessa Jowell and Met Police Commissioner Sir Ian Blair added their messages soon after. Sir Ian wrote: "In proud memory and with an implacable resolve to find those responsible".
With the building still wrapped in Olympic bid regalia, Lord Coe signed, followed by London Transport Commissioner Bob Kiley.
Then a queue including representatives from London's many faith and political groups snaked its way around the City Hall chamber.
Among them was Trevor Phillips of the Commission for Racial Equality, who added: "London, many races, many faiths, one people undivided and undefeated."
The city remained a beacon to the world, which bombers may want to split, but will not be divided, he said.
His message was echoed by Sir Iqbal Sacranie, secretary general of the Muslim Council of Britain, who said his community shared "the pain and anguish of all those who have suffered from this atrocity".
At the ceremony was Olaniyi Falayi, a London Underground station supervisor who on Thursday morning entered the tunnel at Aldgate to rescue trapped victims.
Mr Falayi said the horrific injuries and carnage he saw were still stuck in his mind.
He said of the book of condolence: "It's great that people are able to show their sympathy and empathy to the bereaved families, and all of those affected by it.
"I hope they find solace in themselves and move on. This city should just move on."
Emergency service workers also signed the book
A slow trickle of workers came to sign the book during their lunch hours.
First to sign was David Warren, 49, from Stoke Newington. "We have got to show our respect for the victims and show our defiance to the terrorists," he said.
"You've hurt people, you've blown a bus up, but you're the loser. We've got back on buses and Tubes and we are winning."
Jeremy Mitchell, a Sydney-sider living in London, said he was celebrating London's Olympic bid success on Wednesday in Trafalgar Square. Today, he had come to show he is with London in the good times and the bad.
"I get on the Tube or bus every day. We can't let them dictate to us how we live our lives, because that's what they want to do. Not only kill and maim people but change our way of life.
"The one thing I wanted to do on Thursday was go to a pub and have a beer in central London and say 'no, I'm not going to cower and be afraid'."
Lily Liu, from China but living in Stevenage, Hertfordshire, said she was signing to show her support for the British people.
"I came here thinking Britain is safe compared to the rest of the world. I've been here just a few months and find this is happening. It's just total shock," she said.
Cheow-Lay Wee, a civil servant from Walthamstow, said now was the time for Londoners to stand together.
"Signing the book is one way of expressing our concern but also to show how wonderful it is that Londoners have come together."