My favourite London sound

Peter Cusack mentioned about a Japanese girl whose favorite London sound was the sound of frying onions in her kitchen. The reason she said so was because she just came from Japan to London not long ago. When she was frying onions, the sound of frying made her feeling like being home in Japan. By knowing her preference of London sound, we can learn that she was homesick and the sound was nostalgic for her.
As I have been living in London for quite a few years, I do enjoy listening to many sounds of London. Nevertheless, there is a sound that always touches my heart of missing home. That is the sound emitted from the P. A. system of the Piccadilly line saying-- 'this train is for Heathrow Airport'. When I hear it, I cannot stop wishing that I could take this train and get off at the airport. Then by simply taking the plane, I can return to my family in Taiwan! Yes, I am almost there! Just take this train and get off at Heathrow Airport! I am almost there!
It is always my happiest moment when I can actually complete this wish!