The reader might be forgiven for wondering what there is to be "watched" about tunnels. After all, the greater part of a tunnel lies out of sight underground, and only the entrance and exit can be seen. Even these may not be easily accessible. Again, when under construction these burrowings may not be something the passer- by would find worthy of a second glance. So those whose knowledge lies in other fields may feel that there is no attraction in seeking them out just to look at them.