With its intriguing history and outstanding geologic features, Ha Ha Tonka State Park is one state park that should not be missed. The park is a geologic wonderland featuring sinkholes, caves, a huge natural bridge, sheer bluffs and Missouri’s 12th largest spring. The ruins of a turn-of-the-century stone castle overlook these wonders and offer impressive views of the Lake of the Ozarks and Ha Ha Tonka Spring.