1421
Have you read the book "1421 The Year China Discovered the World"? It is a very interesting book about Chinese maritime history. It suggests America (and also Australia) was discovered by the Chinese hundreds of years before Columbus. In fact, it suggests Columbus (and also Magellan), used Chinese maps during their voyages of discovery.
However the Chinese were not colonisers like the British and Europeans. They were looking for trade. So when they found nothing there, they moved on.
So was Columbus really lucky, or did he have help from the Chinese maps? Interesting book.