The city rests upon the forested hills and rolling prairies of Mid-Missouri, near the Missouri River valley, where the Ozark Mountains begin to transform into plains and savanna. Limestone forms bluffs and glades while rain dissolves the bedrock, creating caves and springs which water the Hinkson, Roche Perche, and Bonne Femme creeks. Surrounding the city, Rock Bridge Memorial State Park, Mark Twain National Forest, and Big Muddy National Fish and Wildlife Refuge form a greenbelt preserving sensitive and rare environments. The Columbia Agriculture Park is home to the Columbia Farmers Market.