At the time of the building of the Festival Hall, my father was involved as he was the London Director of Crittal Windows, the firm who supplied both doors and windows.  The architect wanted clear glass for the main entry doors, but my father explained that these would be dangerous as people would walk into them and be injured.  Instead, he suggested that they should have a bar across, or large handles specially designed.  He also took part in the testing of the acoustics, sitting in various parts of the auditorium.  We went to one of the earliest concerts - the second, I think.  This was performed by Hepzibah and Yehudi Menhuin and we were thrilled, impressed, delighted and really felt that we would have heard a pin, if it had been dropped.  We went to the Circle Bar in the interval.  The view of London from the windows was breathtaking and we really felt peace had come.