Tir Na Nog (Old Irish Tír inna n-OC - roughly means "Land of Youth") is the most popular of Other Worlds in Irish mythology. She is perhaps best known for the story of Oisín, one of the few mortals who lived there, it was said that he was taken by Niamh of the golden hair there. It was where the Tuatha Dé Danann as they settled Ireland 's left surface and was attended by some of Ireland's greatest heroes. Tir na nOg has resemblance to other mythical Irish as Mag Mell and Ablach countries.
Tir na nOg was seen as a place that was outside the map, on an island far to the west. He could either through an arduous journey or an invitation be achieved by one of his fairy tale inhabitants. The island was visited by various Irish heroes and monks in echtrae (adventure) and immram (travel) tales popular during the Middle Ages. This other world was a place where illness and death did not exist. It was a place of eternal youth and beauty. Here came music, power, life and all the pleasant activities together in one single place. Here's the happiness lasted forever, no one wanted food or beverages. It was the Irish equivalent of the Greek Elysium or the Valhalla of the Norse.
Tir na nOg plays an important role in the story of Oisin and Niamh. Tir na nog needed to reach an adventurer a leader in Oisín case plays the role Niamh. They travel together on a magic horse that gallops on the water, the Blessed where the hero spends some time. Finally, a homesick and Oisín wants to return to his homeland. He devastated when he realizes that three hundred years have passed in Ireland since he was together with Niamh, although it seemed to him only one thing. He goes on the magic horse Niamh's home, but she warns him that if he can touch his feet off the ground, he of Tir na exclude nOg forever, but the truth is that the weight of all the years moment his descent would fall on him, and he withered with age and would die. While Oisín, is looking after his family Fianna, he helps two men to move a stone, and he falls off his horse and ages in an instant. He lives just long enough to tell his story Saint Patrick. It is said that Oisín in Elphin, County Roscommon fell from his horse. This story has a striking similarity to many other stories like that of Urashima Taro .
From: Wikipedia
