Thousands of these mounds were discovered in the plains and forestssome up to a hundred feet high, some overgrown hillocks, some conical, others flat-topped.
In a period ranging from 3000 BC to the sixteenth century AD, North American Indians quarried tons of earth to form the monuments, which vary widely.
As George Milner shows, research over the past century demonstrates conclusively that Native Americans built these mounds.
Speculation was rife as to the identity of the moundbuilders.
Thousands of these mounds were discovered in the plains and forestssome up to a hundred feet high, some overgrown hillocks, some conical, others flat-topped