The Bayer Cross in Leverkusen (in German, the sign is known as Bayer-Kreuz) is the largest illuminated advertisement sign in the world. Weighing about 300 tons (600,000 pounds), nothing else comes close to matching the size of this sign, which is for Bayer, the multinational pharmaceutical company headquartered in the region.
Installed in 1958, the advertisement is much different than traditional illuminated signs in that it is not part of a fixed structure. This sign consists of multiple lamps that are set on ropes spun between two masts. This design is resistant to strong winds and gives the illusion of a flying logo at night, when the masts are masked by the darkness. It takes 1,712 40-Watt bulbs to light the display.
While this sign is more than 50 years old now, it isn't the first Bayer Cross. Using a similar design, the first flying logo was built in 1933 between two tall chimneys at the G Power Station. That advertisement was dismantled just over a decade later in 1944.