The Emerald Mound along the Natchez Trace Parkway in Mississippi is the remains of a ceremonial mound built about 700 years ago by Native Americans.
It was part of a town that once sat here, one of many similar settlements in the Mississippi Delta area.
The Emerald Mound stands 35 feet (11 m) high and covers 8 acres (3.2 ha).
A fairly advanced civilization that scientists call the Mississippians lived in the Southeast, building roads, villages, mounds, and other structures.
In about 1450 the civilization declined for unknown reasons.