One of the most famous places in Northern Ireland is Giant's Causeway. Many know it because they watch Game of Thrones or saw it in Harry Potter and the Deathly Hallows. But there's a lovely story that explains how the causeway came to be. One version is here:

Finn MacCool and the Giant's Causeway

Ulster is the most Northern of Ireland’s ancient kingdoms. Its landscape is fabulously beautiful – it has towering cliffs and rocky hills, winding rivers and scooped-out lakes that look like they could have been made by the hands of slightly crazy giants. There are many stone tombs here, five thousand years old, made of enormous boulders that could not possibly be lifted by one man, or even a whole family of ordinary men. For many years the local people have named them “Giant’s Graves” Stories are told of one great Irish Giant, Finn MacCool, whose most fearsome enemies were the Scottish giants. Finn was so angry, and determined to get at them, that he built a whole causeway from Ulster across the sea to Scotland. He built it of unusual six-sided cobblestones, so they would fit neatly together like a honeycomb, and they made a very pretty pavement indeed! One day he shouted a challenge to the Scottish giant Benandonner, The Red Man, to cross the causeway and fight him. But as soon as he saw the Scot getting closer and closer on the causeway, he realised Benandonner was much, much bigger than he had imagined! Finn skidaddled back home to the Fort-of-Allen in County Kildare, and told his wife he’d picked a fight but had thought better of it now. Finn heard the stamping feet of Benandonner from Kilcock, and when those feet got to Robertstown, Finn had to stuff five pounds of moss into each ear. Red Man’s spear was as tall and thick as a Round-Tower, and he used it to knock on the door of the Fort-of-Allen. Finn would not answer the door, so his wife shoved him in the great bath with a couple of sheets over him. Finn’s wife, Oonagh, thought quickly. She opened the door to Benandonner saying, “Sure it’s a pity but Finn is away hunting deer in County Kerry. Would you like to come in anyway and wait? I’ll show you into the Great Hall to sit down after your journey.” Oonagh invited Red Man to look around the room, and showed him what she said were some of Finn’s possessions. “Would you like to put your spear down? Just there next to Finn’s” - It was a huge fir tree with a pointed stone at the top. “Over there is Finn’s shield.” - It was a block of building-oak as big as four chariot-wheels. “Finn’s late for his meal. Will you eat it if I cook his favourite?” Oonagh cooked a cake of griddle-bread – baked with the iron griddle pressed inside it. Red Man bit it hungrily, and broke three front teeth. The meat was a strip of hard fat nailed to a block of red timber; two back teeth cracked. He was given a five-gallon bucket of honey-beer to drink. “Would you like to say hello to the baby? Wait! - I’ll have to feed her first!” Oonagh threw a loaf of bread to the huge baby in the bath-cradle and, peeping out from a huge sheet-like dress and bonnet was Finn MacCool himself, contentedly sucking his thumb. Benandonner said he wasn’t much good with babies. The honey-beer made him feel woozy, and he asked to go outside to clear his head. Oonagh showed Red Man out, where the gardens were scattered about with boulders as tall as the giant. “Finn and his friends play catch with these rocks. Finn practises by throwing one over the Fort, then running round to catch it before it falls.” Of course Red Man tried, but it was so heavy he could only just lift it above his head before dropping it. The blow only ricked his neck - luckily the Scotsman’s head was very hard. But it was also full of good sense. He thanked Oonagh for her hospitality and said he would wait no longer, but return to Scotland before the tide came in. Finn leapt from the cradle, thanked Oonagh for her shrewdness, and chased Benandonner out of Ireland. Passing Portadown, County Antrim, Finn scooped a huge clod of earth out of the ground to fling at the retreating Scot. The hole filled up with water and became the biggest Lough in Ireland – Lough Neagh! The clod he flung missed its target and landed in the middle of the Irish Sea – it became The Isle of Man!! And both giants tore up the Giant’s Causeway, just leaving the ragged ends at the two shores! And if you go to the North coast of Ulster, or to Staffa, the nearest isle of Scotland, you may visit them today – the ends of the beautiful causeway that is, not the giants – those giants are long since in their graves!