A light show took place at the Crystal Palace broadcast tower, located in London, UK on April 18, 2012. The light show marked the switch from analogue to digital television. Arqiva, the Broadcast transmission company that engineered the digital switchover project (DSO), installed over six tons of lighting equipment for the show, and used 200 000 watts of energy-efficient lighting. Our contributor writes that "the show included a beam of light shooting up the tower and radiating out over London, representing the invisible digital TV signals."