The Boott Cotton Mills complex contains mills built from the mid-1830s to the early 20th century, reflecting the early use of waterpower, steam power, and finally electric power. Changes in technology and production capability influenced the development and appearance of the millyard over time. In essence, the Industrial Revolution's transformation of America from an agrarian-based society to an industrial society can be seen through the physical development of the Boott Cotton Mills from 1835 through the early 20th century. Today, the restored mill complex houses the Boott Cotton Mills Museum, a part of Lowell National Historical Park. Photo by Carol Highsmith.