With power readily available from its flowing streams and rivers, Berkshire County was once an ideal place to start woolen, paper, iron, and glass mills. But once that industry left the region, towns were left with empty, mammoth, hulking structures lining the streets and river banks — abandoned mills. Some have since found new life, while others were not as fortunate. Producer Dave Fraser looks at one of the greatest mill revitalization success stories: The Massachusetts Museum of Contemporary Art (Mass MoCA) in North Adams.