Protected areas of water deep enough for ships to anchor safely, usually near a coast; also places of shelter or refuge.
From Old Norse 'hereberrja' (army shelter), literally 'here' (army) plus 'berg' (shelter), originally describing protected places for Viking fleets.
The reason so many major cities exist is basically because of harbours—you need a protected port to trade and get rich—which is why almost every great historical civilization from Phoenicians to Dutch traders built their power on controlling harbours.
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