Fascinating shit regarding the Welsh and Roman incursions into America long before that Columbus fella.
From Red Ice:
Could there be a centuries-long international conspiracy to cover-up the knowledge of ancient visitors to North America? Author Rick Osmon discusses his book "The Graves of the Golden Bear: Ancient Fortresses and Monuments of the Ohio Valley." Rick was selected for the US Air Force Academy right out of high school. He later attended Vincennes University and earned an Associates of Science in Laser and Electro-Optics Technology. For a number of years, he worked for defense contractors and then took a job with the US Navy as a civilian with an engineering support field activity, specializing in radar, night vision, and laser equipment for surveillance and munitions guidance. But, Rick was also reading everything he could find about the weird and unusual, history, archeology, paleontology, geography, cartography, cryptozoology, cryptography, and hollow earth theory. Rick has mapped out the different waves of colonization attempts and visitations to North America. Looking at the claims of the Welsh prince Madoc who is said to have brought thousands of colonists to North America centuries before Columbus.