It looks like your average family car and drives like one, too. But the silver wagon that rolled out of a hangar at Grimbergen Airfield in Brussels at the weekend was much more than an upgraded model.
Concealed under its metallic skin was technology that is expected, ultimately, to drive nails into the coffin of the internal combustion engine.
Even the most conservative technocrats at General Motors, the world's biggest car maker, are buzzing about a green revolution within a decade.
GM's HydroGen 1, the first road-going, hydrogen-fuelled electric car, is a long way from mass production, but it is the first test car of its type - combining fuel-cell technology with pure hydrogen - to prove itself on the highway.
Its vital statistics compare favourably with similar vehicles powered by a 2.5-litre diesel engine: zero to 100 km/h in 16 seconds, a top speed of 140 km/h, and a range of 400 kilometres on a tank of fuel.
As a demonstration of its confidence in the vehicle, GM will use it as the marathon escort car at the Sydney Olympics.
HydroGen 1 drives like an automatic but without the sort of gear ratios used in conventional vehicles - it accelerates more smoothly, and is quieter.
And it's pollution-free.
GM expects that by the end of the decade 10 per cent of all new cars will be using the combination of fuel-cell technology and hydrogen. By 2025, the figure could be a quarter of the world's car market, which is tipped to double to 1.6 billion vehicles by then.
Even more critical, perhaps, is GM's growing belief that cars with fuel-cell "stacks" - collections of 200-odd cells wired in series that generate electrical energy by combining hydrogen and oxygen - will be able to run on petrol by using a device similar to a catalytic converter.
The device re-forms petrol into hydrogen and in doing so cuts carbon dioxide emissions dramatically, in line with car makers' greenhouse promises.
But GM says that converting petrol is an interim measure.
Winning the pollution fight would almost certainly depend on the world's eventual conversion to hydrogen, which produces no pollutants.
"This is the only energy carrier that will be able to satisfy the need for a lasting reduction in carbon dioxide emissions despite a steady increase in the number of motor vehicles on the roads," says Dr Erhard Schubert, co-director of GM-Opel's Global Alternative Propulsion Centre, which has research facilities in Germany and the United States.
"This is because it reacts electro-chemically with oxygen in the fuel cell to yield water."
Dr Schubert says the enormous potential of the fuel-cell car is that it will one day be powered by hydrogen derived from renewable energy sources such as hydro-electric, wind or solar.
He referred to Jules Verne's description of water as "the coal of the future", adding: "Today, we know just how right he was."
GM unveiled HydroGen 1 at the Paris car show two years ago but the fuel-cell technology, cloaked in Opel's European-made Zafira five-seater van, had yet to undergo trials at the group's testing facility at Dudenhofen in Germany, and it was using hydrogen re-formed from methanol. The significance of GM's latest revelations - which also include breakthroughs on engine temperatures and on-board fuel storage - is that it has now fixed on pure hydrogen as the road to the industry's future and is ploughing hundreds of millions of dollars into the project.
Although its goal is still a long way off, GM's public commitment to hydrogen-powered vehicles ahead of methanol and other fuel sources is certain to accelerate the race with other car makers to put a viable fuel-cell car on the road.
Its chief rival, DaimlerChrysler, wants to produce such a car by 2004 and have 100,000 fuel-cell vehicles on the road by the following year.
Honda, which is promising hybrid models powered by combined petrol and electrical motors as soon as next year, expects to produce small numbers of fuel-cell vehicles as early as 2003.
GM executives say they are not worried about losing the race, only about having a vehicle with the best technology ready to launch later this decade.
"What we are saying is that we want to be in a position to make a strategic decision in 2004," said one executive at the weekend demonstration. "The danger of going into production too early is that within a year or two your competitors might bring something out which supersedes your model. Timing is crucial."
Fuel cells are not a new idea; they have been around since the 1830s and have been used in the US space program.
Nor is the idea of electric cars new; GM launched its own, the EV1, four years ago, but the two-seater sports coupe was a fizzer and in January the company suspended production. All up, GM sold just 1,400 electric vehicles.
Cost was the killer.
The EV1's price was about 30 per cent more than that of a conventional car, a fact which sceptics seize on as the millstone for new-generation fuel-cell vehicles.
GM says it is well aware of the problem, citing its own research which showed, as Dr Schubert puts it, "that consumers will not pay one extra cent for the sake of the environment".
However, the latest breakthroughs have made GM increasingly confident that a fuel-cell car can compete on price.
Just how willingly consumers take to a new form of energy is another question.
However, converting petrol products into hydrogen as an interim measure will at least give the car makers and oil companies time to convert consumers and establish hydrogen filling stations.
GM is cagey about how much it has spent on HydroGen 1, but some say the figure is well over $US150 million ($247 million).
DaimlerChrysler expects to spend at least $US1 billion getting its model to the assembly line.
Dr Schubert says only that GM's spending is a nine-figure sum, adding that his budget for the coming year is similarly healthy.
'It's a very good amount, and we can certainly do a lot of things with it."