Question

When did they Build the Serpent Mound

Answer 1

between 800 B.C. and A.D. 100.

Step-by-step explanation:

Answer 2

In 2014, another research team carbon-dated a number of other charcoal samples, placing the construction of Serpent Mound between 381 B.C. and 44 B.C., with a mean date of 321 B.C. The new evidence suggests, once again, that the Adena were the original builders of Serpent Mound.