In July 1997, more than 150 years of British rule came to an end in Hong Kong with its handover to China, a historic event viewed with a mixture of uncertainty and hope.
We asked observers how their predictions turned out 20 years on, reports the BBC.
Would Hong Kong remain China's 'golden goose'?
Back then, cosmopolitan and prosperous Hong Kong was seen as China's vital gateway to the outside world - and many believed it would stay that way for years to come.
Fast forward 20 years, and it is no longer the only jewel in China's crown, with cities like Shanghai, Shenzhen and Guangdong becoming financial or manufacturing powerhouses.
"Hong Kong was the golden goose in China," said politician Martin Lee.
"I couldn't have thought that China's economy would develop so quickly… and Hong Kong's bargaining power would diminish so fast."
Many also did not envision Hong Kong ending up as "a paradise for money laundering and capital outflow" for the mainland, said financial analyst Agnes Wu.
In recent years Chinese tycoons have sought to park their assets, businesses and even themselves within the city amid a corruption crackdown in Beijing - something which the Chinese government has frowned upon.
Would democracy spread to China?
Many wondered in 1997 how the reunion of a freewheeling, liberal city with its tightly-controlled mainland would pan out, particularly a few years after the Tiananmen Massacre which saw the brutal crushing of pro-democracy protests.
One hope was that Hong Kong could eventually "infect China with democracy", said Keith Richburg, a former correspondent with The Washington Post.
With China's rapid pace of economic development, many believed it would open up politically as well, and "if Hong Kong could just hold on for 20 years, there would be a convergence".
Some believe the opposite has happened.
Last month, Hong Kong's last British governor Chris Patten said there had been "a steady tightening of grip on Hong Kong's windpipe" and its autonomy.
China has promised to preserve the city's rights and autonomy under the "one country, two systems" principle.
But there are fears it is not keeping that promise, following the disappearance of Hong Kong booksellers and a Chinese tycoon and Beijing's intervention in the selection of Hong Kong lawmakers.
China now sees Hong Kong "as a threat... a base of subversion, a place to be controlled," said Mr Richburg, particularly after a series of large-scale protests culminating in the 2014 pro-democracy demonstrations.
China has also become emboldened by "the fact it's become clear that outside powers, including Britain, are not going to make any trouble... it's got a pretty free hand," said Jonathan Fenby, a former editor of the South China Morning Post newspaper.
Growing up in post-handover Hong Kong
But others disagree. Hong Kong's chief executive-elect Carrie Lam recently told the BBC that "one country, two systems" is as "robust as ever", and rule of law is "better than pre-1997".
Ms Lam, a former civil servant, is herself an example of Beijing keeping its promises, according to politician Regina Ip.
"Without the reunification, a lot of us local administrative officers (like Ms Lam) would not have risen to the top.... To this extent, 'Hong Kong people ruling Hong Kong' has been fulfilled," said Ms Ip.
She believes the relationship between Hong Kong and the mainland needs more time to evolve.
"'One country, two systems' is proving to be more complex and more challenging than originally expected," she said, but she hopes outstanding issues "will be resolved in the coming years, sooner rather than later."
What would happen to Hong Kong's identity?
With the handover, "many of us thought it would be only natural that young children were going to learn the (Chinese) national anthem, and learn to respect and love China in their classes," said anthropologist Gordon Mathews.
Beijing had thought Hong Kong would embrace this return to the Chinese motherland after decades of foreign rule, said observers.
Instead, Hong Kongers ended up developing a strong sense of local identity, one that is often defined by anti-mainland sentiment.
Hong Kong journalist Ching Cheong recalled that in 1997 one worry was of "mainlandisation" where Hong Kong's values would be eroded, turning it into "just another Chinese city".
"But something that I didn't predict took place instead - the appearance of localism, or separatism," he said, referring to the political movement where some advocate independence from the mainland.
Local identity has only been strengthened with perceived attempts by Beijing to exert influence.
Singer Anthony Wong says "many people started caring about their own rights" following attempts to introduce mainland-styled anti-subversion laws and national education in Hong Kong, which sparked large-scale protests and a "political awakening".
But others like Hong Kong business magnate Allan Zeman believe that assimilation is inevitable.
"In the next 20 years, things are going to change... we have the bridge between Hong Kong, Macau and Zhuhai, we have the high-speed rail. These infrastructures will change Hong Kong and eventually the borders will become seamless."
"Hong Kong will integrate more in China, whether we like it or not."