The town has been transformed over the past century. Prior to World War I, the town was one of the most industrialised in the UK, with its economy entirely dependent on industry on the River Cart, River Clyde and in the textile mills. Housing was most commonly 2, 3 and 4 storey tenement flats or in 18th century cottages. At this point, the town's population was pushing 100,000 and these people were contained in only a few square miles. Overcrowding was a major problem and disease spread quickly.