Penn's Cave was opened to the public in 1885, when a hotel was built on the site. Today, the cavern and the Penn's Cave House are listed on the National Register of Historic Places. Reaching the cave's entrance, we descend a flight of stairs that leads to the long, red motorboats, each of which holds 22 people. White and colored lights illuminate walls and columns that rise to the ceiling 40 feet above us. The cave, about 20 feet wide on average, was formed millions of years ago from the bed of a shallow sea.
Ducks swim alongside the boats in water two to three feet deep.
We wind our way out the back of the cave, where the spring empties into Lake Nitanee, a five-acre lake made in 1925 to support a hydroelectric plant. The plant attracted so many visitors that, two years later, an opening in the cave was blasted so tourists could reach the lake by boat. Swans glide gracefully on the lake, while, in the distance, we see a deer. The thousand acres of forests and fields have been preserved as a natural habitat for birds and animals, including elk, turkeys and wolves. Wolves howl in the wildlife sanctuary that's part of the Penn's Cave attraction.