Pierre L'Enfant, the man who planned Washington D.C., wanted to have a park in the middle of the city. However, the National Mall was not always a park. In the 19th century, there was a railroad that ran through the Mall. Cows also grazed (ate grass) on the Mall. There was a large market on one side of the Mall. During the American Civil War, there were many buildings on the Mall. There were even slaughterhouses on the Mall - places where animals are killed and turned into meat. In 1901, the Senate passed the McMillan Plan. This cleaned up the National Mall and moved the railroad to Union Station.