Adena Complex burial mound in the Ohio Valley, probably the largest humanly produced ancient mound in the Americas. The mound is about 21 m high with a basal diameter of 73 m. It contains an estimated 54 500 metric tons of soil (70 000 cubic metres). Around the mound was a moat 10 m wide and 1.5 m deep. It is a mortuary mound over a high‐status burial, constructed in the 3rd or 2nd century bc.
T. Hennings, 1984, Investigations at Grave Creek Mound 1975–76: sequence for mound and moat construction. West Virginia Archaeologist, 36.2, 349