Here is presented the widely dismissed account that probably sometime in the mid-11th century, Danish Vikings from Schleswig and the Danelaw (as ascertained from runic rock inscriptions) arrived at Santos in Brazil and proceeded inland to Paraguay. From a fortified hill near the Brazilian border, they occupied a defensive position for some part of two centuries, keeping watch on a nearby small mountain. It has been reported that in the 20th century, beneath the mountain under observation, was discovered a large area whose walls and roof are built of concrete unknown to science and cannot be opened but are believed to conceal a network of tunnels. The following unravels the story presented by just a few advocates, of Vikings in