The Adena Culture emerged in the Ohio River Valley sometime between 1400 and 800 BC, and persisted until around 300 AD. Adena raised earthen mounds ranging from just a few inches to nearly 70 feet high (21 meters). Within the mounds, the honored dead were buried in sub-mound pits, log tombs, and occasionally elaborate timber structures. The human remains from the mounds were frequently found with artifacts, including copper bracelets, beads, and gorgets, as well shell, flint, and slate objects.