This article is brought to you by the years 3500 to 2000 B.C.E!


Let's say you're playing a video game.  You need to start human civilization.  No big deal.  You have a big wide map before you, and you have a lot of little player characters who are hungry and ready to work.  Where will you place them?  We will need water, of course.  We will need good soil to plant crops.  We will need a way to ship goods in and out of the city and a fast way to travel to and from the city.  With these needs met, we can build our civilization.  Next to the river?  Great.  Between two rivers?!  Even better.  Excellent.  I see you've played this game before.  


Welcome to the land between two rivers!  Or . . . Mesopotamia.  There, that's catchier.  It's right in the Middle East where all civilization started.  This was the beginning of cities and grids and laundromats and lattes.  Why does it all start here and not somewhere else?  The answer is simple: lots of water and flat land.  Your little civilization between two rivers will have crops grow as quickly as you can plant them.  Farming is when people grow their own plants for food or raise animals for food.  Look where all the other game players put their people: not by rivers.  Without water, they have to wander around just to look for food.  What else do you have going for you?


It's more than water that makes your land between two rivers so valuable.  Silt is the sand and clay left behind by running water.  In the spring months, your rivers will overrun their banks, flooding the land.  (Game tactic: don't build houses in that area.)  Not only is the dirt the water leaves behind easy to plant in, it's also very rich.  Your crops nearly leap out of the earth toward the sun with all of the nutrients they get from this soil.  Your civilization is doing very well!  The people living by the rivers have lots of food and lots of work.  Time for the next level.


Other civilizations have to wait for rain to come to wet the seeds buried under the earth.  The two rivers give you water day and night, all year round.  Irrigation is when people bring water to different places to help them farm.  By building channels out from the river, you can grow your civilization away from the river.  You can now make water branch into more land that doesn't get as much water.  More and more people join your civilization and you grow more and more food.    


It only gets better from here.  Your water is so plentiful, your dirt is so healthy, and your irrigation stretches so far that you start to grow more food than you have mouths to fill.  Surplus is the extra stuff that is not used right away and can be stored to use when you need it.  A lot of your crops can now be used during the winter months, when you can't grow as much.  This is the first sign of true civilization.  


Now that you have all this food, guess what?  You don't need as many farmers. Division of labor is when each person can have one job and become very good at one thing, instead of doing many different things.  With well-fed people covering agriculture, everyone else can take on new jobs, like trade, weaving, writing, and way down the road, making games like this one.  This is another sign of civilization.  


Yes!  You beat the game!  Your civilization is growing more quickly than any other because you placed it right between two rivers.  The extra water and rich dirt make sure you'll be able to grow lots of crops.  This makes a surplus, which means you have more food than you need, and would-be farmers can work in other trades, like weaving or game-making.  Building next to a river isn't just a good way to win this game.  It also helped many real civilizations begin.  Egypt began by the Nile.  China began by the Huang He, or the Yellow River.  India began next to the Indus.  In this game, you did WAY better than the player who decided to put all of his people into the desert where they have struggled to start a civilization.  They're . . . not doing so hot.  


References:

Art History World.  "Early River Valley Civilizations"  arthistoryworld.org, 2014.  <http://arthistoryworlds.org/early-river-valley-civilizations/>