Hy-Brasil is a legendary island that appeared on ancient maps from as early as 1325 until well into the 19th century. On most of these maps, it was located in the North Atlantic, approximately 200 miles (321 kilometers) off the west coast of Ireland. One of the most characteristic geographic features of Hy-Brasil on these maps is that it often appears drawn as a circle with a channel (or river) running from east to west across its diameter. For centuries, stories about this island have circulated throughout Europe, with accounts claiming that it was the promised land of the saints or a paradise inhabited by an advanced civilization. In Irish...