Sand gapers are large shellfish. The large shell valves, which you sometimes find on the beach, don't close entirely. They gape a bit. That is why this animal is called a sand gaper. Originally, they came from America. The Vikings brought this animal from North America to Europe. That may not seem so strange. However, the Vikings lived before Columbus. The presence of sand gapers in Europe indicates that the Vikings had contact with America. This means that Columbus was not the first to travel to America.