Between 1938 and 1946 the Swift River Valley was flooded for the Quabbin Reservoir, erasing four towns: Dana, Enfield, Greenwich and Prescott. On the land that never went under, their street plans, house-lot outlines and cellar holes are still imprinted in the earth.
Turn on LiDAR relief and zoom in. The grey is MassGIS 1 m bare-earth LiDAR, the ground with the forest digitally removed, and the old roads, walls and foundations read straight off it. Check what you find against the Historical map (1890s and 1940s surveys), or turn on Reservoir water to see what drowned.