Falls of the Ohio State Park in Clarksville sits on the north bank of the Ohio River, across from Louisville. It is best known for its exposed fossil beds, which preserve the remains of ancient marine life from a time when the area lay under a shallow sea. Visitors can walk along the river's edge, look for fossils in the rock and take in views of the falls and the Louisville skyline. The interpretive center explains the geology, wildlife and history of the area, including its role in the early settlement of the region. Entry is $7 per vehicle with Indiana plates and $15 for out-of-state vehicles, and the interpretive center costs $9 for adults and $7 for children. Water levels affect access to the fossil beds, so check conditions before you go.