The hell´s hole, a cavity with a pothole created by the sea and a curious shape which communicates with it at 43 meters of depth. Sea cave which has the particularity of having the ceiling destroyed by the horizontal and vertical erosion caused by the sea. There are many legends related to this furna like for example the noise which was originated from the inside, the echo of the waves which caused the inhabitants to be scared and some more legends around this furna, like the existence of a golden thorn bull which protected the entrance to the hole, the entrance to the world of the dead.
These beliefs were influenced by the presence of sounds which the colonies of guillemot made (this bird no longer exists). They nested in Ons as well as the European Shags and galos mariños in Ons. These sounds were dangerous for the inhabitants because they attracted people to the hole, running the risk of falling into it.
.When a member of the community disappeared, people went to the hole to look for it in case the sea could have put it there. There was a procession with torches waiting for the person to appear. It was leaded by the preacher, if he was on the island, and a woman like those (this was the way the witches were called, coming from the continent when they were required). Torches were thrown into the hole so that the corpse could be damned.
