A rectangular tunnel entrance looks a little sinister. I picture the Sierra Madre and an abandoned gold mine ready to collapse while the good guy is hiding from a bunch of bad guys who have automatic weapons. It's dark in there, it's scorpion and rattle snake infested, there's an old shovel, a water canteen, maybe a big bat, and a couple of bleached bones, all that's left of Humphrey Bogart.
It's times like these a person begins to wonder about the Saints. Saint Barbara,
who was removed from the calendar of Saints by the Pope in 1969 following doubts
about the authenticity of her story, does spring to mind as a possible name for
a Tunnel with a Rectangular Entrance. In her life, as I understand it, she had a
way with lightning and those who specialize in the use of explosives, such as
miners and artillerymen, have called her their Patron Saint.