An object lesson in how to conceal a 1¼ ha. Underground reservoir. It has been set into the hillside and the excavated soil used to create gentle mounds on the other side of the road. Grass covers the water storage area and trees and shrubs have been planted around it. The reservoir is a fine example of the philosophy that the landscape architect (in this case Sir Frederick Gibberd) succeeds best when nobody knows he has been at work. Harrow Park, Harrow-on-the-Hill.