Did you know that on this day in 1868 the world’s first traffic lights were installed in front of the Palace of Westminster in London? They used railway technology with semaphore arms for day-time use and green or red gas lamps at night, but it was only a year before they randomly exploded, injuring the constable that was operating them. Traffic signals have come a long way since then, and have made their way into contemporary art in myriad ways, including Robert Rauschenberg’s experimental prints, Iván Navarro’s atmospheric installations, and Pierre Vivant’s discombobulating public sculpture, which now resides near Billingsgate Market in Poplar, London. The Traffic Light Tree was commissioned by the Public Art Commissions Agency, and features seventy-five sets of lights, which are computer operated. Many passersby have also noted its decidedly festive aesthetic.