September 11, 2001 was already destined to be an important date in the life of architect Daniel Libeskind. It was the day that 13 years of labour would come to fruition with the opening of his spectacular project, the Jewish Museum in Berlin.
The museum duly opened its doors to the public for the first time that morning, only to close them again almost immediately as news filtered through of the terrorist attacks on the World Trade Centre and the Pentagon.
Thus Libeskind was catapulted from his first project into his next great task - the redevelopment of the Ground Zero site in New York, of which he has grandly been designated the "master planner".
The two projects, although very different, do have things in common other than that fateful date. Both are about rebirth from a tragedy - and both have a huge personal resonance for Libeskind, who was born in Poland to Holocaust survivor parents in 1946 amid the devastation wrought by war, and who arrived in the New York 13 years later on an immigrant ship which docked near where the Twin Towers were later to be built.
Libeskind, in London to address an event hosted by the charity One Family UK in support of victims of terrorism in Israel and around the world, acknowledges the huge personal meaning of both projects. "Of course you cannot compare 9/11 to the Holocaust but both signify the permanent struggle in life and the permanent threat to democracy and culture that is there, whether from terrorist groups or from whole populations being brainwashed."
This brings him naturally to one his most strongly held beliefs about architecture - that one of its main functions is about the collective memory.
He explains: "Memory is not about remembering a fact or about recalling information. Memory is the complete intellectual and emotional immersion in the event itself. It is about understanding in depth the consequences of the event both backwards and forwards in history. It has to resonate in the soul. Without that resonance we would just be machines, robots with no empathy or understanding about what those facts mean for ourselves or for others. Memory is a key dimension for orientation in our lives, and architecture is all about orientating people."
However, his radical designs certainly do not evoke the past in a traditional way - his angular, asymmetric designs appear futuristic. Libeskind ponders for a moment. "The reasons my designs may appear futuristic or even jarring is because memory is something which has to be awakened in a very radical way. It can be compared to tradition. Tradition can be a rote ritual without any meaning unless, with each action of the individual, there is a connection to the flame of why that tradition started in the first place. This is the urgency that memory represents for me."
Libeskind is certain that his background has informed his work, and also feels that architecture has always been important for Jews. "If you go back to the Mishnah and the talmudic commentaries you will see there are whole chapters and books devoted to the importance of architecture in the Jewish tradition. It's not just about an aesthetic external image, but rather about the action that gives it life."
He also has a peculiarly mixed cultural upbringing which, he is sure, has added texture and context to his work. He was born in Poland and spent his childhood there before first moving to Israel and then three years later, as a teenager, to the United States. "In Poland, we were Jewish and we were almost unable to be a part of society because of that. I remember the light of Israel contrasting with the grimness of communist Poland and being able to identify freely as a Jew for the first time. Israel and America, the two promised lands, have had a very big influence on how I see architecture. Of course, you can't be anyone except who you are."
Although now regarded as one of the world's greatest architects, Libeskind was a late starter. He did not finish his first building, the Jewish Museum in Berlin, until he was in his 50s. Before that he had been an academic and a writer on architecture, confined to the conceptual level. Although he was always sure that one day he would have the chance to realise some of his designs, his confidence was not shared by critics who labelled his work unbuildable. He has a sense of having lived his life in reverse - the first part of his career spent in reflection and the second half in fevered activity.
He says: "Most people who are architects start by getting an apprenticeship, designing a small building and developing their skills. That was never my interest. Rather, I took a path through music, through intellectual pursuits as a professor. I never designed a building before the Jewish Museum, so it's a different way of looking at the world. I think of architecture more as a cultural endeavour."
Indeed, Libeskind, who was a prodigious pianist as a teenager, thinks architecture is closely related to music. "Music speaks to us in a way which is very mysterious. You can listen to a symphony, a concerto or a song and it can link you to the world. Architecture is very similar in that way. There is a spiritual aspect which is almost indefinable. We can talk about the music, the chords, or the space and dimensions, but ultimately the effect is on memory and personality."
So does he regard himself as a spiritual person? Libeskind laughs. "Everyone is spiritual. Even atheists are believers. They have to be or they wouldn't deny it."
Libeskind may well have had an easier time of it had he stayed in music. He concedes that "musicians seem to live very long lives". However, he does not feel he has left music behind. "I feel like I am playing a different instrument now. It's a different kind of performance. Architecture is more complex. If you are the kind of person who gets frustrated that Ground Zero is taking a long time to finish, you will be misunderstanding what architecture is,. It is compromise which makes it the ultimate art. It is not practised privately, it is practised with others. It is a civic art."
Not that Libeskind confines himself to the great projects. He has also returned to his first love by producing a revolutionary design for a grand piano. "I hope it will go into production. Architecture is like a beautiful musical instrument. A Stradivarius has to be played. Likewise, a building is not an empty shell. A building can encourage creativity in the same way. If we live in a sad city we are not fulfilled as human beings."
He adds: "Life is not about an office, a museum , a park; it's about connecting those things and obliterating those categories. Life should be beautiful. Thatis what l'chaim means - that life itself should be celebrated."