Who all explored the Mississippi.

There was a civilization there before we discovered it.

Explanation:

They were called the Mississippians. The Mississippian culture was the largest and most complex society that lived in prehistoric Tennessee. Mississippian people lived in and around the state from about 1,000 A.D. to 1,500 A.D. This group is also referred to as the mound builders, because they built many large ceremonial mounds within fortified towns.

county governments

well this is going to be a long answer lol ok so the visigoths were a branch of the goths who frequently raided rome, uh the hunas attacked the guptas a lot and weakened them, uuhm of course the romans used math and science in there every day lives i mean they had a whole empire to run, and rome was split into east and west by a general named diocletian. hope this you! : )