"America" was discovered by Europeans
Quite possibly by an Irish monk, St Brendan the Navigator back in sixth century. Maps of Christopher Columbus' time often included an island denominated Saint Brendan's Isle that was placed in the western Atlantic Ocean. You should check out the documentary The Brendan Voyage. A British explorer undertook the journey across the Atlantic using the type of boat Brendan is likely to have had.
"Tim Severin and his companions built a boat using only techniques and materials available in the sixth-century A.D., when St Brendan was supposed to have sailed to America. The vessel comprised forty-nine ox hides stitched together in a patchwork and stretched over a wooden frame. This leather skin was only a quarter of an inch thick. Yet Severin and his crew sailed Brendan from Brandon Creek in Dingle to Newfoundland, surviving storms and a puncture from pack ice."