AFTON, Va. (AP) — Hikers and bicyclists can now explore a historic railroad tunnel in Virginia’s Blue Ridge Mountains after nearly two decades of restoration efforts.

The News Virginian reports that the Claudius Crozet Blue Ridge Tunnel Trail system opened to the public Saturday.

The nearly mile-long tunnel was constructed between 1849 and 1859.

Considered an engineering marvel at the time, the Blue Ridge Tunnel was designed by renowned French engineer Claudius Crozet.

Irish immigrants and enslaved laborers built the tunnel. It had to built using hand tools and black powder, as dynamite had not yet been invented.

Railways stopped using the tunnel in 1944. CSX Transportation donated the tunnel to Nelson County in 2007. Officials have been working to restore the tunnel since 2001.

The trail has parking lots on both sides and visitors need to bring their own lights to see.