The Vikings came from the rugged,  inhospitable north known today as Scandinavia. As the Roman Empire  flourished further south, Scandinavians had small settlements,  no central government, and no coinage. Yet by the 11th century, the Vikings  had spread far from Scandinavia, gaining control of trade routes  throughout Europe, conquering kingdoms as far as Africa, and even building outposts  in North America. The secret to their success  was their ships. The formidable Viking longship had its origins  in the humble dugout canoe, or log boat. For millennia, the inhabitants of Scandinavia  had used these canoes for transportation. Dense forests and tall mountains  made overland travel difficult, but long coastlines  and numerous rivers, lakes, and fjords provided a viable alternative. The first canoes were simply hollowed out  logs rowed with paddles. Over time, they added planks  to the log boat base using the clinker,  or "lapstrake," technique, meaning the planks overlapped and were fastened to each other  along their edges. As the Roman Empire expanded north, some Scandinavians  served in their new neighbors’ armies— and brought home  Roman maritime technology. The Mediterranean cultures  at the heart of the Roman Empire had large warships  that controlled the sea, and cargo ships that transported goods  along the waterways. These ships were powered by sail and oars and relied on a strong skeleton  of internal timbers fastened to the outer planks  with copper, iron, and wood nails. At first, Scandinavians  incorporated this new technology by replacing their loose paddles  with anchored oars. This change  hugely improved the crew’s efficiency, but also required stronger ships. So boat builders began to use iron nails  for fasteners rather than sewing. They abandoned  the log boat base for a keel plank, and the boats became higher  and more seaworthy. But these early ships retained the concept of the original log boat: their strength  depended on the outer shell of wood, not internal frames and beams. They were built as shells—  thin-walled but strong, and much lighter than the Roman ships. Competing chieftains quickly refined  the new ships to be even more efficient. The lighter the boat,  the more versatile it would be and the less investment of resources  it would require— an essential advantage  in a decentralized culture without large supplies of people. These ships still had no sails—  sails were costly, and for now the rowed ships  could meet their needs. That changed  after the Western Roman Empire collapsed in the 5th century. Western Europe  took a heavy economic blow, leveling the playing field a bit  for the Scandinavians. As the region revived, new and vigorous trade routes  extended into and through Scandinavia. The wealth that flowed along these routes helped create a new, more prosperous  and powerful class of Scandinavians, whose members  competed constantly with each other over trade routes and territory. By the 8th century,  a sailing ship began to make sense: it could go further, faster,  in search of newly available plunder. With the addition of sails, the already light and speedy ships  became nearly unbeatable. The Viking ship was born. Viking longships could soon carry  as many as 100 Vikings to battle. Fleets of them  could land on open beaches, penetrate deep into river systems,  and be moved over land if need be. When not at war, the vessels were used to transport goods  and make trade journeys. There were smaller versions  for fishing and local excursions, and larger adaptations  for open sea voyages capable of carrying  tens of tons of cargo. Thanks to their inventiveness  in the face of difficult terrain and weak economies,  the Vikings sailed west, settled the North Atlantic  and explored the North American coast centuries before any other Europeans  would set foot there.