China is planning on creating World's greatest Mega City: 42 Million people.

9 Cities will be merged into one (Guangzhou, Shenzhen, Foshan, Dongguan, Zhongshan, Zhuhai, Jiangmen, Huizhou and Zhaoqing)

The whole area will be about 16,000 Sq. Mile.
Total Costs: around $330 billion. (USD)
Project is expected to take 6 years.