An abandoned vertical iron mine that is now home to one of the largest hibernating/breeding bat colonies (up to 1 million bats) in North America. Mine shaft entrance is covered with a special steel grate to prevent people from falling into the shaft; but allows bats to come and go as they please. There is a self-guided interpretive program at the site to inform visitors on the benefit of bats. Best times to view bats is right at dusk in Apr/May and Sept/Oct when bats leave or enter the mine to hibernate. It is designated as an official Michigan Wildlife Viewing Area.