The Bayer Cross (German: Bayer-Kreuz) in Leverkusen is the largest illuminated advertisement in the world. The advertisement is for Bayer, the multinational pharmaceutical company based in Leverkusen. The advertisement, installed in 1958, shows the emblem of the company Bayer. It hangs on two 118-metre steel towers and possesses a diameter of 51 metres and a weight of 300 tons. It takes 1,712 40-Watt bulbs to light the display. In 2003, the Bayer cross was overhauled completely.
An older Bayer Cross existed before World War II. This was erected in 1933 and placed between two 126-metre chimneys of a power station; it had a diameter of 72 metres. It was dismantled in 1944.