Academics have put forward detailed plans for a tunnel to join Taiwan with China, even though unification is remote.
The shortest proposed route would come to 126km -- more than twice the length of the Channel Tunnel, which provided the inspiration for the Chinese plans.
An alternative route using bridges to link intermediate islands would be almost twice as long again.
A recent conference in Xiamen, co-sponsored by universities from Taiwan and China, brought together more than 70 experts with the blessing of the Chinese government.
In a message, Fujian Province Governor Xi Jinping said: "Construction of a cross-strait tunnel has become a dream of the Chinese people."
Fujian is the province from which most Taiwanese originate and where both proposed routes would begin.
At the moment there is no direct passenger access between China and Taiwan.
However, the experts argue that it is better to start research sooner rather than later, despite the lack of government funding.
Tsinghua University professor Wu Zhiming told the conference: "The special feature of macro-economic projects is that the period of preparation vastly exceeds the period of construction."
Wu listed as examples of his argument the Channel Tunnel, which required 14 years of planning -- and which had been discussed for two centuries -- and the huge Three Gorges dam on the Yangtze river, for which preparations began in the 1950s.
China should be ready when the "moment of opportunity" arrives, argues Wu, who first became committed to the project after taking Eurostar to Paris while visiting Britain.
Just as the Channel Tunnel had to wait until European integration became sufficiently advanced, so the Taiwan tunnel will require political rapprochement across the Strait.
The Xiamen conference fo-cused on the more ambitious southern route, which would use Kinmen and Penghu as stepping stones.
The first stage of the new project could be a bridge to span the 5km between Xiamen and Kinmen.
Kinmen politicians have visions of thousands of Chinese tourists crossing by bridge to help revive the island's economy, which has been hit by the scaling-down of Taiwan's military garrison.
The longest tunnel now being planned anywhere in the world is the 54km land tunnel to link Lyon in France with Turin in Italy, which will not be completed until 2015-2020.
It will take even longer before the Taiwan tunnel is built -- if at all.
But in a country where mega-projects like the Three Gorges dam remain in official favor, it does not seem wholly unrealistic as it might elsewhere.
"There is no problem on the technical side," the Global Times newspaper, owned by the Chinese Communist Party, claimed: "The only difficulty is to pass the political test."
RSS