Back in 1990—top—Shanghai looked like a lovely green city. Only twenty years later—bottom—you can film the second part of Blade Runner in it.
Shanghai has always been an important place. Located on the Yangtze river's mouth, this Chinese city was already a world commerce hub back in the 30s. But it wasn't until Deng Xiaoping's economic reforms that the city exploded. Only fifteen years later, it became the largest cargo port in the world. Twenty years later, it's the megalopolis you are seeing in this photo.