That said, once you have looked at a picture of the mural, I strongly doubt you'll come away thinking that it's a picture of Vikings.
Nature is trying much harder to destroy anything of archeological significance in the jungles of central and South America and the Atlantic coast of the Northeast US and Canada. We're just never gonna have great information about these societies because a much larger fraction of the stuff they left behind will be gone.
It isn't, it's gone. The image in the article is a watercolor reproduction made in the 1920s-30s. And even when they found it, it was as deteriorating fragments on the floor, which were subsequently lost to a hurricane.