All cities change, and nothing stays the same forever. This is ofcourse obvious, but not something I would really think about when I visit a new city: I observe the city, the urban landscape, the culture and the people. And I think to myself how this city is different to other cities I know well. A bit harder but a just as good question would be: How has this city changed over time, and how will it change in the future?
Typically cities make it easy to see it's history: In most cases most buildings are decades old, and many restaurants and shops have been around for at least years. On top of that you can often find historical landmarks and museums for this exact purpose. The future on the other hand, is very hard to predict.
But not for Hong Kong, Hong Kong is on pretty a fixed timeline: A deal agreed in 1997 between an old dethroned world superpower (the UK) and a rising new world superpower (China) says that Hong Kong shall have limited change for 50 years.
While the full 50 years have yet to play out (nor what comes after), China has been pretty clear in it's overall long term objectives. It has been pushing for some of these already just as I spend some time here, with the expected resistance from most people who live in Hong Kong.
Generally speaking protests (especially those widely covered) are a signal of cities and socities going through change. But not in the part of Europe I'm from, protests are considered a normal and healthy part of public debate). I grew up around protests, and there were a number of them at my university in Amsterdam in the few years I attended (such as Occupy Amsterdam). The big difference between Hong Kong and Amsterdam is that Hong Kong is undergoing rapid change (as it has for at least a century), while Amsterdam really hasn't changed all that much - and the beauty of the city came from wealth generated 400 years ago.