When Viking longships encountered Mediterranean trading galleys, enterprising shipbuilders combined the two designs. The result was the carrack, a sturdy, square-rigged ship with three masts that retained the longships' sturdy construction (necessary in the treacherous northern seas) and the maneuverability of the Mediterranean trade ships. This combination allowed carracks to foray into waters never before seen by European eyes -- and to carry back goods and maps from those faraway lands.