Fitchburg grew rapidly in the 19th Century as an industrial center, as did many New England communities. Importantly, the Nashua River runs through the city. Originally run by water power, large mills produced machines, tools, clothing, paper and firearms. The city is still known for its architecture, particularly in the Victorian style, built at the height of its mill town prosperity. A few examples: The Fay Club, the old North Worcester County Courthouse and the Bullock House.