Rapid urbanisation

In 2015, 85% of global GDP was generated in cities. Growing cities require substantial investments in infrastructure if they are to continue expanding at their present rate. It’s estimated that we will invest $78 trillion in global infrastructure over the next 10 years alone to accommodate this growth. New York, Beijing, Shanghai and London will need $8 trillion in infrastructure investments alone. 

Do these figures surprise you? Do Homework
What challenges do modern urban planners face? Do Homework
What changes would you like to see in Tokyo in the future? Do Homework