There are hundreds of underground manmade stone chambers in Massachusetts of unknown origin and conjectured purpose. There is much debate and controversy over this. Everything from Irish Culdee Monks to Colonial's root cellars to Native American construction has been proposed. From inside, some of these chambers view significant celestial events, and most are tall enough to stand up in.
Open-bottomed precast concrete or plastic structures, which are placed next to each other in an excavation to take the place of crushed stone in a leach field. Unlike leach fields, heavy-duty chambers can be driven over.