A railway runs right through the middle of a residential building, while dizzying skyscrapers glow in bright neon colours: this is Chongqing, the cyberpunk-style Chinese metropolis of over a million people, often described as the world’s largest city. Like Beijing or Shanghai, it is a symbol of Chinese power.

Photojournalist Alessandro Gandolfi offers a glimpse behind the scenes of the impressive skyline, whilst geographer Michel Lussault explains how these megacities have become instruments of influence and control.