The Lowell National Historical Park tells the story of the Industrial Revolution and the changing role of technology in a 19th and 20th century setting. The cultural heritage of many of the ethnic groups that immigrated to the United States during the 19th and 20th century, which continues today, is still preserved in Lowell's neighborhoods. The park provides a vehicle for economic progress in the community, encouraging creative and cooperative preservation and interpretive programs.Innovative partnerships have resulted in nationally acclaimed projects such as the Tsongas Industrial History Center, a partnership between the National Park Service and the University of Massachusetts Lowell. The park and its numerous partners also co-sponsor the Lowell Folk Festival, the largest free folk festival in the United States. The festival presents three days of traditional music, dance, craft demonstrations, hands-on-activities, street parades and ethnic foods on six outdoor stages along the canals and throughout the downtown historic district.