The Pilates Method, more commonly known as Pilates, is a popular kind of physical activity and exercise that aims to improve the body's strength and flexibility. Pilates began early in the 20th century. Joseph Pilates, a German boxer and circus performer who, during World War I, was forced into an internment camp, developed it. While in that camp he developed floor exercises to help keep himself healthy and rehabilitate his fellow detainees. After the war, Joseph Pilates came back to Germany and trained the Hamburg Military Police for a short period. He eventually moved to the United States, where he met his wife. The two of them worked together to improve the Pilates method and invent special equipment.