Emergency switch to stop the escalator at Potsdamer Platz station, Berlin, Germany, Europe

berlin buildings building central europe deserted emergency switches emergency switch empty escalators escalator europe german federal republic germany journey middle europe nobody no one no people potsdamer platz potsdam square railway station building railway station republic of germany staircase stairs stairway stair stations station stop button stopping stops stop train station buildings train station building train station travel photography trip uninhabited