These Iconic Walls In Ireland Have Lasted Years, But Are Held Together By Nothing

Ireland is known for its rolling green hillsides and expansive skies. Yet if you travel across the Emerald Isle, you'll notice something else, too: hundreds and hundreds of miles of stone walls zig-zagging across the fields. These intricate walls parcel the land into strange shapes that seem to have no reason at all behind them. They look like they should be marking out property lines, but there's nothing around, save for miles of intersecting stone walls. So what are they? The walls criss-cross the sides of the Partry Mountains in County Mayo. Flickr / Stacy First, a little geology: Ireland...