Perspectives: Zion tunnel and windows

Can you see the dark spot almost in the middle of the image? That is a window into the Zion-Mount Carmel Tunnel.  The tunnel was built from the late 1920's to 1930.  

From this site:  The arduous task of constructing the tunnel, undertaken by the men of the Nevada Contracting Company, along with crew bosses from around the country, began with blasting gallery windows into the cliff face above Pine Creek Canyon. From these windows the crews were able to then access the interior of the cliff and progressively bore their way through the rock, ever approaching opposite ends of the cliff where the tunnel would meet the new roads. The gallery windows also served as holes through which rock debris from carving the tunnel could be pushed out and cleared from the work area, as well as supplying much needed ventilation and lighting to crews working inside the tunnel.

Driving through the tunnel was great as was peaking out of the windows as we moved along.