Hamm is an industrial city in the province of North Rhine- Westphalia, originally producing a good bit of coal. The Lippe River flows through the city and becomes a part of an intricate canal system used throughout the area to transport much of the raw materials and manufactured products. Hamm is also an important railway city with a downtown section surrounded by five communities. There is a DuPont plant similar to the one in Chattanooga in the Unetroop section of Hamm, and some DuPont employees have lived and worked in both cities. Dr. Robert Collins and his family lived in Chattanooga and were transferred to Hamm. It was his friendship with the Mayor of Hamm which led to the Sister City affiliation.