In the 60's and 70's(?) the dairy producers in US were getting high demand for low fat milk such as skim and 2%. This meant taking out massive amounts of fat from large amounts of milk. All this fat had to go somewhere, so the dairy producers turned it into cheese and butter.
In turn, their was more cheese than anybody had a use for, so the United States government decided they would buy the cheese in order to sustain the dairy industry.
The buying of cheese went on for many years and all the cheese got stocked in huge caverns in the state of Missouri. At it's peak there was over $4 billion of cheese. That's right, $4,000,000,000 of cheese stockpiled in these caverns.
Reagan then came into power and was all "wtf do we do with all this cheese??", so he decided the government would stop buying cheese.