Prince Madoc was an explorer and navigator par excellence! 
"Madoc's landing place has also been suggested to be "Mobile, Alabama; Florida; Newfoundland; Newport, Rhode Island; Yarmouth, Nova Scotia; Virginia; points in the Gulf of Mexico and the Caribbean including the mouth of the Mississippi River; the Yucatan; the isthmus of Tehuantepec, Panama; the Caribbean coast of South America; various islands in the West Indies and the Bahamas along with Bermuda; and the mouth of the Amazon River".[7] Although the folklore tradition acknowledges that no witness ever returned from the second colonial expedition to report this, the story continues that Madoc's colonists travelled up the vast river systems of North America, raising structures and encountering friendly and unfriendly tribes of Native Americans before finally settling down somewhere in the Midwest or the Great Plains.[8] They are reported to be the founders of various civilisations such as the Aztec, the Maya and the Inca."
https://en.wikipedia.org/wiki/Madoc
Any time now, Mormon historians are going to discover that Prince Madoc was also the founding father of the Nephites!