Edward Kirk Warren (1847-1919), a philanthropist and industrialist, began his career as a dry goods merchant in Three Oaks and became a millionaire after inventing featherbone in 1882, a cheaper, more flexible material than the whalebone used as stays in clothing. Convinced it was vital to preserve forest and dune land in Southwest Michigan for the enjoyment and education of future generations, he bought hundreds of acres there. In 1918, he and his wife, Mary Louise Chamberlain, created the Edward K. Warren Foundation to manage and preserve the land. After his death, the foundation worked with the State of Michigan to create Warren Dunes and Warren Woods State Parks. Warren Woods, called "the last known stand of virgin beech-maple forest in southern Michigan," was designated a National Natural Landmark in 1967. About 4,500 years ago, wind pushed beach sand onto the land and created the dunes at Warren Dunes. The Edward K. Warren Foundation and the State of Michigan partnered to open Warren Dunes State Park in 1948. Covering more than 1,000 acres, it included nearly three miles of shoreline and sand dunes more than 200 feet tall. In 1976, the state legislature passed the Sand Dunes Protection and Management Act to begin safeguarding sand dunes throughout Michigan by restricting development, and protections were strengthened in 1989 by the Critical Dunes Act, which designated Warren Dunes as a Critical Dune area. By 2016, the park had grown to nearly 2,000 acres and was attracting almost one million visitors annually.