For years, researchers have puzzled over why Viking descendents abandoned Greenland in the late century. But archaeologists now believe that economic and identity issues, rather than starvation and disease, drove them back to their ancestral homes.
Architecture: Trelleborg is six Viking Age circular forts, located in Denmark and the southern part of modern Sweden. Five of them have been dated to the reign of the Harold Bluetooth of Denmark. All trelleborgs have a strictly circular shape.