There are three.... Suez Canal; Straits of Gibraltar & the Bosporus, to & from thre Black Sea.
The two main waterways in the midwest are the Mississippi and Missouri Rivers.
I'd have to say Christianity for certain and with the rise of Islam, then Islam is number two.
The Alps and the Carpathians.
New York and Philadelphia were the two main ports that shipped to all europe.
quien sabe
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For electricity and for transportation.
Europe and The Pacific.
The two main countries in western Europe are Germany and France. It would not be totally accurate to say that they dominate western Europe. There are other large and important countries there too.
Europe and Asia
There are two waterways that could be used. The Mediterranean sea or the Red sea were both quick, efficient waterways that the Egyptians COULD of used.
Catholicism and Protestanism were main and Anglicanism began as an 'interweaving' of these two. See related link below: