On Wednesday, still warm from the glow of Saturday's Live8 concert in Hyde Park, London felt like the centre of the world, a place you would not want to leave. On Thursday, it felt like the centre of the world in a very different way, a burning hellish centre in which the world's violence had converged.
In the space of a week we have been brought from above the stars to our knees. Perhaps we forgot, in all the jubilation of the Olympics triumph and the preoccupation with the G8 summit, that there were bombs waiting to go off. Perhaps Tony Blair himself momentarily forgot; as one friend said after watching Mr Blair's grave speech from Gleneagles on Thursday: "He took his eyes off the ball."
For months, even years, Londoners have boarded the Tube with a sense of quiet recklessness; it could be today, it could be tomorrow. The rescue services have waited in the wings.
London, typically, does not cope well with disaster. Rainfall brings road-rage and traffic of epic proportions. Heavy snow brings worse, slushy filth and trains at standstill. Tiny disasters happen every day on London's streets, robbings, killings, attacks. But almost as quickly as it falls, the city gets back up again.
On the television news during Thursday's blasts, reports of casualties and fatalities were quickly followed by what was going on with the FTSE All-Share, the strength of the pound against the dollar. As people walked home along the river, the buses empty, the Tube desolate, there was already talk of resumed services the next morning. Yesterday, those who had not developed a temporary Underground-phobia in response to the attacks, boarded the wounded service and went back to work.
Although Thursday's attacks are hardly comparable in scale to the destruction that was the Blitz, there has been much talk of the stoicism that the British people have once again demonstrated. The initial panic underground when the bombs detonated was followed by eerie calm.
Individuals assumed heroic roles and pregnant women were paid special attention. Others took pictures on crippled mobile networks, or talked to reporters, still shivering, still crying, with patches on their faces and burns on their skin. It feels much like another world war. How could there not be stoicism? And how could there not be kindness?
On Thursday evening, I walked in the fading light. The streets were quiet. There was a sense of hurt and humility in the air. In the newsagent, as the woman at the counter gave me my change, she said, quietly: "Take care." I went to get dinner from a West Indian takeaway. It was full of people ordering dumplings and roti. There was music in the background. The women serving the boys were smiling and batting their lashes.
Far from wanting to leave London, Thursday's atrocities have made me all the more determined to stay here. This is where I live.