I believe most of them had to be VERY close.  (Check a map of Ancient Egypt....available in most books on Ancient Egypt), to see.  Obviously(?), Egypt is , (mostly) an arid and dry country....almost a desert!  The only thing that made civilization, (cities, towns, organized villages), really possible there, were the life-giving waters of the Nile River!  It allowed irrigation, which meant crops could grow....which meant FOOD!   Also, the Nile River was a great source for ships and trading vessels of all kinds, (and from all countries), to take "short-cuts" for trading.  The Nile River was one very BIG reason why Ancient Egypt was one of the world's first great civilizations!  

If other history buffs are like me, they are interested in History a lot more than they are in geography.  But geography often plays a very, very big role in history.  Like Napoleon's (and Hitler's) defeats, caused by the bitter Russian winter!  And the flourishing of a great ancient civilization, due to Egypt's Nile River!