On several weekday’s nights in winter, I went to the underpass under all corners of the Terazije square – one of the “hearts” of Belgrade. This space is defined by echo, a counterpoint of sound performing itself. The portals to the world above create a sonic line. It is acousmatic, perceptually detached beyond recognition from the discrete source of the sound. It is just a line. In the underground passage, “the echo displaces the linear relation of origin and horizon, past and future, by prolonging the sound event to a point where it takes over” (LaBelle 2010: 7). Materializing as a strange body, “the echo… [stages] [the passing of sound] as a performance” (LaBelle 2010: 6-7).