Mexican-Canadian artist Rafael Lozano-Hemmer's interactive light and sound art installation inside the Park Avenue Tunnel called Voice Tunnel outfitted the 1,400-foot long Park Avenue Tunnel with loudspeakers and 300 theatrical spotlights that produce glimmering arches of light along the tunnel’s walls and ceiling. The tunnel was illuminated with pulsating lights "powered" by visitors' voices. Louder speech increased the lights’ brightness proportionally, creating a Morse-like code of flashes throughout the tunnel. The individual voices were heard as pedestrians walk through the tunnel, on 150 loudspeakers, one beside each light arch and synchronized with it. At any given time, the tunnel was illuminated by the voices of the past 90 participants: as new participants speak into the intercom, older recordings got pushed away by one position down the array of light fixtures, so that the content of the piece changed constantly. (Description of the art installation from the Summer Streets official website).