Wausau has evolved from an 1800s lumbering town on the Wisconsin River into a thriving city with a diverse commercial and industrial base. A 10-square-block historic district preserves a sense of the city's past. Its present includes an oriental influence. Wausau is a center for the buying and selling of ginseng. In fact, Marathon County is the world-leader in the production of this medicinal root so valued in the orient. Just south of town is one of the oldest geologic formations on earth, Rib Mountain. Its observation tower affords breathtaking views of the Wisconsin River Valley.