Bayer AG is a German multinational chemical and pharmaceutical company founded in Barmen (today a part of Wuppertal), Germany in 1863. It is headquartered in Leverkusen, North Rhine-Westphalia, Germany, where its illuminated sign is a landmark. Bayer's primary areas of business include human and veterinary pharmaceuticals; consumer healthcare products; agricultural chemicals and biotechnology products; and high value polymers. The company is a component of the Euro Stoxx 50 stock market index.Bayer lost its US business after World War I and during World War II was part of IG Farben and participated in Nazi war crimes. IG Farben was broken up after WWII and Bayer became independent again, and in 1978 it bought back its name in the US.Bayer's first and best known product was aspirin; there is a dispute about what scientist at Bayer made the most important contributions to it, Arthur Eichengrün or Felix Hoffmann. Bayer trademarked "heroin" and marketed it as a cough suppressant and non-addictive substitute for morphine from 1898 to 1910. Bayer also introduced phenobarbital, prontosil, the first widely used antibiotic and the subject of the 1939 Nobel Prize in Medicine, the antibiotic Cipro (ciprofloxacin), and Yaz (drospirenone) birth control pills. In 2014 Bayer bought Merck's consumer business, with brands such as Claritin, Coppertone and Dr. Scholl's. Its BayerCropscience business develops genetically modified crops and pesticides. Its materials science division makes polymers like polyurethanes and polycarbonate.