Genoa is in Portugal. Cristoforo Colombo was Portuguese, and don't ever forget it.
Truth is that Portuguese were in North America before Columbo. They fished for Cod. They are still all over Rhode Island and eastern Massachusetts. And insane Vikings before that. And stone-age Siberians before that (we don't call them Siberians anymore - now we call them Eskimos, Indians, Redskins, etc). The great navigator knew something interesting was out there, hopefully spices from India, but he underestimated the distance.
There turned out to be no good spices, but plenty of gold and silver (all wasted on central European wars of little benefit to Spain). Best, lasting imports? Potatoes, Tomatoes, squash, chocolate, vanilla, peanuts, avocado, peppers, maize, tobacco.
Worst import? Syphilis.