I mean Lichtgrenze.

The LICHTGRENZE is the light installation along the former path of the wall through the city center. It will trace the division of the city over a stretch of approximately 12 kilometers and with thousands of illuminated balloons as an impressive installation in Berlin from 8 to 9 November, 2014. At once emotional, poetic, and serious, this installation remembers the recent historical event, the fall of the Berlin Wall on November 9, 1989.