The 3:10 to Yuma was headed to the Yuma Territorial Prison, as were we the day after we toured Castle Dome. It is now a museum- a good one. You can see the cells and learn about the notable prisoners and administrators- and gain insights into Arizona history.
An archway leading into the locked area:
At first it almost looks like a church window- but it’s a view through a cell. In person, there are NO similarities to a church!