Roundup is a weed killer that has the most glyphosate. It was created by Monsanto in 1974 and it is used to kill weeds all over the world. Roundup was originally created to be sprayed on crops, but it is now also being sprayed on residential lawns, gardens, public parks, and playgrounds. It is used to kill weeds all over the world and is especially popular in the United States. Roundup contains the active ingredient glyphosate, which works by inhibiting an enzyme that is essential for plants to grow. Without this enzyme, the plant cannot produce the proteins it needs to survive, and it will die.