(continuing) I'm supposed it, 3,000~4,000years ago, could have 1) a better temperature and weather change for ocean, different vision from recent 100years. 2) People sailing on the sea knowing mutual and satellite setting between simple boat, wind, sea-level and marine creatures. 3)There's no plastic, industrial waste, heavy metal or vessel to ruin....Anyway, all people could imagine it's quite FAR.