Austin is believed to be the only city in the world that still operates the "moonlight tower" system of lighting that was popular in the early 1900s. Although only 17 of the original 31 remain, the 150-foot towers still provide lighting in several areas of the city.
Originally, the towers provided light via a carbon arc lamp, which was then a new technology. Over the years, the towers have gradually been upgraded. Today, all towers use 6,400-watt mercury vapor bulbs, and their lighting is fully automated.