Whatever you think about China, you gotta give them some credit for their public transport. Right now, China's total metro system length is almost equal to the rest of the world combined.
- China: 11003.004 km (6,855.591 mi)
- Rest of world: 12632.24 km (7,847.44 mi)
Furthermore, out of 12 longest metro systems in the world, 11 are in China. The remaining one is in Russia. Just crazy numbers.
This is probably unachievable in Western countries, since they expect the metro systems to make a profit, which makes no sense whatsoever. Some don't, of course, and they, too, have respectable subway configurations.