Old Tunnel State Park is a railroad tunnel of the Fredericksburg and Northern Railway, which ceased operations in 1942. The property came under the care of Texas Parks and Wildlife Department, and was officially made a state park in 2012. It is located halfway between Fredericksburg and Comfort on Old San Antonio Road. Since the shut down of the railway, the tunnel has become a bat cave, hosting over 3 million Mexican free-tailed bats and 3000 Cave myotis bats. The bats emerge at sunset during the months of May through October, and viewing is open to the public.