Volta do mar
Portuguese sailors developed the navigational technique known as the volta do mar (literally 'turn of the sea') in the late fifteenth century, exploiting a clockwise wind circle known as the North Atlantic Gyre.
They brought their vessels home from the Canary Islands or Madeira by sailing northwards toward the Azores before picking up westerly winds that brought them back to Europe when conditions did not permit a direct return along the African coast.
Similar gyres operate elsewhere, running clockwise in the North Pacific and anti-clockwise in the South Atlantic, South Pacific and Indian Oceans.
