Louisville is situated at the Falls of the Ohio, an ancient limestone ledge that disrupts the course of the Ohio River. When European explorers and settlers began arriving in the mid-1700s, they discovered few signs of permanent Native American settlements in the region, which was used as hunting grounds by Cherokees from the south and Shawnees from the north. However, archaeological evidence suggests a continuous human presence did thrive in the area that became Louisville from at least 1000 BC until sometime around 1650. During this time the Adena culture and the subsequent Hopewell tradition thrived in the area, and hunting villages sprang up along Mill Creek and on the bluffs overlooking the Ohio River near today’s Zorn Avenue. According to archaeologists, the very first humans to come to the area that is now Louisville were Paleo-Indian nomadic hunters, who followed herds of animals into Kentucky at the end of the Wisconsin glacial period, around 13,000 BC.