In many stories, myths and sagas, the Celts speak of the existence of 'The Other World'. Time and again their descriptions plunge us into a world in which, for example, our sense of time does not occur at all.
One also finds other names for this 'Other World', such as: the Land of Youth or the Land of the Ever Living.
This other world was not a country that was inaccessible to ordinary earthly people, otherwise we would know nothing about it of course.
The Celts always cherished The Other World as a place of wisdom, the place of their gods and the dimension where poets feel most at home.
There was also a fountain of wisdom in this world, and in Irish mythology it was the Well of Conla or the Well of Segais. Manannan, the god of the sea and king of The Other World, declares that this well contains five salmon and has five streams forming the five senses. Everyone who would obtain knowledge, had to drink from the fountain, and those who also drank from the five streams were the people of the arts. These people are of course the bards or the poets.
We also see drinking from the well of wisdom in the Edda, in which Odin had to drink the divine drink from the well of Mimir in order to become the ruler of the power of speech.
However, getting to The Other World was not easy; you had to do something special for that, or you had to be invited to do it. But this 'invitation' often took place without one knowing it. In other words, when the inviters were interested in you, you were simply taken there.
The geographical location of this special area varied, because sometimes this world was below sea level, in the middle of a mountain or in the middle of the ocean. One thing can be said for sure: in principle, this country was in the immediate vicinity of Ireland.
When we think of a mysterious place in the middle of the ocean, the submerged Atlantis inadvertently springs to mind. That is certainly not surprising, for according to W.Y. Evans Wentz the drowned land of Atlantis is a certainty for the Celt and the 'Other World' is clearly related to this. Evans Wentz believes that the sinking of this continent made a deep impression on the souls of the later populations of those regions and that they therefore placed the drowned land of Atlantis in myths and legends.
Rudolf Steiner has also indicated in his writings that the stories told by the Celtic Druids were based on an unconscious memory.
The Celts were convinced that Atlantis had existed in the distant past and gradually sank into the ocean. They have attached this primordial memory to an even older memory, namely that of paradise lost. Both of these memories persisted in the souls of the people who later wrote them down and formed the source of the sagas and myths known to us.
The Other World was the refuge for their dead heroes and the gods retreating from the world. The realm of the Other World was of the ever-living, where anything was possible and great deeds were accomplished. Life there had been enhanced to perfection and continued with all the joys of food, drink, love and bliss.
The Otherworld was so beautiful and wonderful that it inspired the Celtic poets, with their eloquence, to create melodious lyrical verses.
Many wonderful travelogues to the Other World have been left to us and even formed a new genre of story: the Immrama.
One should take into account the fact that in the distant past the population still had clairvoyance, in which they could perceive the world of the gods with their etheric body. Their world just looked different from ours.
Certainly, the initiated Druid saw the gods, could confer with them and thus guided the people. Over time, however, this clairvoyance diminished and eventually disappeared to make way for the current consciousness, which is more focused on the physical world.
If then the clairvoyant Druids could still see the gods, later they would have to make do with only the perception of elemental beings, which in Ireland were called 'fairies'. Hence, certain plants, trees, and springs were held in high esteem because they were the abode of certain elemental beings.
Hans Gsänger writes in his book 'Irland'  that we do not find the 'Other World' only among the Irish Celts. The Greeks also knew the land that lay far in the western ocean. They told about an island where, in exceptional cases, ordinary people could come to live a blissful life.
For the Greeks, the titan Atlas and his daughters the Hesperides lived in the western and nocturnal region of the ocean where also the origin and abyss of heaven and earth would lie.
The Hesperides dwelt on an island to which no ship could gain access, and where they guarded the golden apples that were not for the common people, but for those capable of superhuman deeds.
Aeschylus, Pherecydes and Apollodorus believed that Atlas and his Hesperides were located north of the Rhipäen ocean, so in the vicinity of Hyperborea. So Hercules went a longer way than we initially assume to get the golden apples from the Hesperides!
The Hyperboreans are mentioned by the ancient Greeks, such as Herodotus and Pausanias. They had a religion that was dominated by Apollo and can therefore also be compared with the Bel or Sun religion of the Celts and Germans.
In principle, the Hyperboreans still lived in the paradisiacal condition, in which man was not yet denatured by his fall.
They were also called the "long-lived" because their lives sometimes spanned hundreds or thousands of years. Rudolf Meyer writes in connection with this fact that in the Finnish epic, the Kalevala, Wäinämöinen, the primeval singer and sorcerer, lay in the womb for seven hundred years before he was born. This already indicates that in the Hyperborean period man lived in his ethereal light form in which he did not yet know death, but a change and transformation or rejuvenation of his life form.
We also come across the aforementioned 'Immrama' in the 'Other World'. These are stories about people who find access to that other, supersensory world and have a special experience there.
Characteristic of the situation in the Immrama are the following:
• One no longer has the physical body
• Only paradise apples serve as food
• There is no eroticism and sexuality
• The sense of time is different
• The moment of death and cause of death of the mortals is known in the other world
The stories often (but not always) describe a certain initiation, which is depicted in colorful and imaginative images.
The Immramas are reminiscent of the Greek adventures of Odysseus, and the Celts describe these experiences just as the Greeks envisioned the life of the Hyperboreans.
One of the most famous Immramas is the story of Ossian or Oisin, the son of Fionn mac Cumhaill.
Irish writer William Butler Yeats  has artfully depicted his autobiography in the following story:
The wanderings of Ossian
Ossian is led to the Other World by the fairy Niamh on a white horse. He lived there with his fairy undisturbed and at peace for 300 years, but then Ossian becomes homesick and longs to return to Ireland to rejoin his beloved lineage of the Fianna. His wife, the fairy Niamh, warns him three times never to put his feet on the ground, and furthermore tells him that he will never again meet those he knows. But all that makes no sense. He goes back, and to his great regret finds out that his wife was right. And how Ireland had changed! He now finds out how long he's been gone, and roams on his horse around all the places where he's ever met his family, the Fianna, without seeing anyone he knows. Then he encounters a group of men who are carrying a heavy tombstone to a cemetery. They ask the young man to help, Ossian bends down but falls from his horse. The moment his foot hits the ground, his horse is back in fairyland and Ossian suddenly becomes an ancient, blind and broken man!
 William Butler Yeats, The wanderings of Oisin, London: Kegan Paul & Co, 1889
 Caitlín Matthews, The Elements of Celtic Tradition, Element Books, 1989
 Hans Gsänger, Irland. Insel des Abel. Die irischen Hochkreuze [Ireland. Isle of Abel. The Irish high crosses], Verlag Die Kommenden, 1969