A piece of beauty

Strange thing happened on our way back home from the cinema and weekly shopping.
I don't know how can I describe this with a word diifferent than "strange", because this was not normal.
One of the main streets of our town, buses, cars, noise, people walking from or to restaurants, pubs or clubs, Saturday evening city chaos... We are standing on the bus stop and, out of blue, we hear beautiful classical music. It is difficult to locate the source at first. Then we realise than some parts of the building opposite, on the other side of the street, is covered with red material, and there is a speaker hidden in one of the windows. Suddenly, a person appears on the balcony of the building and starts singing - an opera song!
People started to gather around. They were staring and listening, totally mesmerised. Those in cars, in buses or on bikes were turning their heads around.
We decided to stand in cold for about ten minutes instead of taking the first bus home, to be able to listen to the performance. After the lady in black, who was really amazing, there was a man singing two songs, one in Latin and one in English, and then another lady. I wish I had a better phone, soe I could record it...
It was something incredible. A piece of extraordinary beauty in the middle of a random place and time.