The families of the three Leeds men who killed themselves and 52 innocent people in the July 7 2005 attacks are still looking for answers 10 years on, an imam has said.
Qari Asim said the community was left in "shock and disbelief" after discovering the suicide bombers were from the Yorkshire city.
And the imam of the Makkah Mosque in Leeds said questions were still being asked over how three seemingly ordinary, friendly young men could carry out such atrocities.
Mohammed Sidique Khan and Shehzad Tanweer both grew up in the Beeston area of the city, while Hassib Hussain was from Holbeck.
The three men travelled from Leeds and, with a fourth man Germaine Lindsay, detonated bombs across the transport system in London.
Mr Asim, whose mosque is in the Hyde Park area of Leeds, said: "I didn't know the three perpetrators, who came from Leeds and committed the atrocities on 7/7, but I have known the families and everyone that knew those three young men, they were saying they were like ordinary young men, they were gentlemen, they were good to talk to, they were very friendly people effectively.
"And I think that's the key challenge that makes it even worse for the Muslim community and the ordinary British citizens, how can three young men, living their ordinary lives, become so radicalised? Can be so motivated that they can take their own lives but also take the lives of others?"
He added: "Ten years on and the Muslim community, and the wider community, we are all still looking for answers, we are all still trying to find out what are the factors and what is the evidence that leads to radicalisation.
"The families of those three men who came from Leeds and blew themselves up in London, they are still looking for answers because to them they would never have imagined that their young men would do something like that and they're still going through this sense of shock and disbelief."
Mr Asim said communities in Leeds came together following the bombings to send out the message that they would not be defeated by terrorists.
"7/7 was a particularly horrible day for people of Leeds. When we heard the news that the perpetrators had come from Leeds we were in a complete sense of shock and disbelief. Never in a million years did we think that something like that would happen on our soil, in our country," he said.
"But I'm really pleased to say the communities really came together, the people of Leeds came together and I think they came together because they did not want the terrorists to win."
At the weekend, the Leeds Peace Ambassadors, a group of young people from different faiths, will undertake a "peace journey" from Leeds to London, retracing the steps of the three Yorkshire bombers.
Mr Asim said: "Their aim was destruction, their aim was misery, their aim was to cause mayhem, whereas this peace journey is all about bringing peace to our world.
"Why are we taking this journey? Young people will be reflecting on how do they see the world, where are we going, what went wrong 10 years ago and what lessons we can learn from the mistakes that we made in the past."
The imam said relationships between different community groups in Leeds are now stronger than ever before and will be celebrated with an event at Elland Road stadium on the evening of July 7.
Mr Asim said: "On 7/7, the citizens of Leeds are coming together in large numbers at Elland Road, which is a symbolic place, to really say 'enough is enough', to really say that we are all in is together, that we have much stronger relationships with each other than 10 years ago and we can together defeat terrorism, fanaticism and fascism."