China has always been isolated by geographic protections. The highest mountains in the world separate it from India; vast amounts of semi-desert land separated it from Mesopotamia. In the south flowed the Yangtze river for 3000 miles, navigable from the sea for half of its course. In the north was the Yellow river, known for its disastrous tendency to flood. | China has always been isolated by geographic protections. The highest mountains in the world separate it from India; vast amounts of semi-desert land separated it from Mesopotamia. In the south flowed the Yangtze river for 3000 miles, navigable from the sea for half of its course. In the north was the Yellow river, known for its disastrous tendency to flood. |