When I moved to Hong Kong in 1973, Mao Tse Tung was still alive, the cold war was on, the Vietnam war was on. Then starting 1978, the breakdown of socialist communist policies began.
The real opening started in 1989 - 1990. The changes in the world have been mind boggling. Nobody could have expected the lands where nothing at all 20 years ago, which is now modern cities.
Equally in the 1920's nobody could have expected where Detroit was probably one of the richest cities in the world, that the city would disintegrate as much as it has.