The Otherworld (Andumnos) - also known as Andumnos, is just beyond our senses. We can sense it, and sometimes almost feel it, because it's around us, next to us, in front of us. And when we dream we're on the borders of the otherworld, nearly touching it. It is possible to venture in and out, with discipline in mind and training, and the wisdom learned is immense. It is here in the otherworld that the "Fée", the Gods, the spirits, and the Ancestors dwell -

The otherworld is separate from us, because of "the veil." It's a barrier built to keep mortals and the dead from meandering back and forth, to create order and boundaries. On two nights of the year it thins, and some say it wears completely through, and the two can intermingle.

And there are places of locii that contain doors, or gates, to the otherworld. There are deities with these areas, or spirits (genius Loci or anima loci). This can be a tree, a mountain, a cave, a lake, a certain rock, etc., or if a mist is thick enough it can be a gateway.