The shimmering skyscrapers and neon haze of boomtown Shenzhen are testament to the border town's spectacular rise since gaining special economic zone status almost three decades ago.
Because of the rapid transformation of the once quiet fishing village and farmland community into one of the mainland's trade and industry powerhouses, Hong Kong came to view its emerging neighbour as a threat to its long-held dominance in the region's trade and business.
But with the more recent emergence of greater Guangdong as a booming industrial heartland, there is growing support for a merger of Hong Kong and Shenzhen into a mega-metropolis.
The idea was given its latest hearing last month when the highly respected Bauhinia Foundation suggested that Hong Kong and Shenzhen join hands to create, by 2020, a mega-metropolis and economic powerhouse that eclipse such world cities as London, Paris, Chicago or Los Angeles.
The foundation's 10-point blueprint included introducing a multiple-entry electronic smart card for Shenzhen permanent residents to enter Hong Kong, a rail line between the two cities' airports and jointly developing border land in the Lok Ma Chau Loop.
All of the suggestions are aimed at enhancing the flow of people, goods, services, information and capital between the two cities. Last month's proposal argued that if the combined metropolis maintained 8 per cent growth a year until 2020, its gross domestic product would reach US$1.11 trillion, surpassing Tokyo and New York.
The proposal to merge the two neighbours is nothing new: Shenzhen made the first overture to Hong Kong about 10 years ago but received a cool response. A decade later, Hong Kong's attitude has changed dramatically, and the government is promoting the concept.