On the night of July 15, 1989, the Venice lagoon filled with the sound of Pink Floyd's rock music booming from St. Marks' basin. The memory of the concert's atmosphere and an account of the objectives, facts and consequences associated with this event provide an opportunity to reflect on the use of history and of the urban space, on the conflicts running through the city, and the connections between that which is persistent and that which is temporary. In the words of Manfredo Tafuri, "l'ephemere est éternel".