The first tunnel was blasted through the rocks of Sideling Hill in 187374 for the East Broad Top Railroad.
This was followed by at least a couple more.
The original railroad tunnel ceased operation in 1956, and the one opened in 1940 is now abandoned.
Instead, they decided to cut a deep notch across the hill and lay the road through it.
Some fossils, mainly plant remains and some marine invertebrate shell casts, were also found at Sideling Hill.
The exhibit center was closed in 2009 due to state budget cut.
