Two giants of the farming and chemical industries agreed to merge Wednesday in a $66 billion deal: the U.S.’s Monsanto and Germany’s Bayer, the original maker of aspirin. It’s the year’s biggest deal and will create the world’s largest supplier of seeds and farm chemicals, with $26 billion in combined annual revenue from agriculture. If the merger goes through, it will combine two companies with a long and storied history that shaped what we eat, the drugs we take and how we grow our food.

Bayer: Then & Now

Two friends making dyes from coal-tar started Bayer in 1863, and it developed into a chemical and drug company famous for introducing heroin as a cough remedy in 1896, then aspirin in 1899. The company was a Nazi contractor during World War II and used forced labor. Today, the firm based in Leverkusen, Germany, makes drugs and has a crop science unit, which makes weed and bug killers. Its goal is to dominate the chemical and drug markets for people, plants and animals.

Monsanto: Then & Now

Monsanto, founded in 1901, originally made food additives like saccharin before expanding into industrial chemicals, pharmaceuticals and agriculture products. It’s famous for making some controversial and highly toxic chemicals like polychlorinated biphenyls, now banned and commonly known as PCBs, and the herbicide Agent Orange, which was used by the U.S. military in Vietnam. It commercialized Roundup herbicide in the 1970s and began developing genetically modified corn and soybean seeds in the 1980s. In 2000, a new Monsanto emerged from a series of corporate mergers.