CN Tower
In 2007, light-emitting diode (LED) lights replaced the incandescent lights that lit the CN Tower at night, the reason cited being that LED lights are more cost and energy efficient than the incandescent lights. The colour of the LED lights can change, compared to the constant white colour of the incandescent lights. On September 12, 2007, Burj Khalifa, then under construction and known as Burj Dubai, surpassed the CN Tower as the world's tallest free-standing structure. In 2008, glass panels were installed in one of the CN Tower elevators, which established a world record (346 m) for highest glass floor panelled elevator in the world.