A solar-powered car has arrived at the UN climate change talks in the Polish city of Poznan after a round-the-world trip covering almost 40 countries.
At the wheel of the "solar taxi" was Swiss teacher Louis Palmer who made the 52,000km (32,000 mile) 17-month trip.
He said the feat proved solar power was a viable alternative to oil-based fuels and could help fight global warming.
But he said the prototype would need serious modification before it could be mass produced.
The small blue-and-white three-wheeler tows a trailer packed with batteries charged by the sun. It can travel for 300km on a single charge and reach speeds of 90km/h (55mph).
"People love this idea of a solar car," Mr Palmer said outside the venue of the UN climate talks. "I hope that the car industry hears…and makes electric cars in future."
Mr Palmer, 36, said the car ran "like a Swiss clock," breaking down only twice during the gruelling trip through 38 nations starting in Lucerne in July 2007.
Passengers included UN Secretary-General Ban Ki-moon, Monaco's Prince Albert, Hollywood filmmaker James Cameron, New York Mayor Michael Bloomberg and Sweden's Prime Minister Fredrik Reinfeldt, he said.
The car runs on solar power but Mr Palmer also had a battery for travel at night or in less sunny nations, such as winter-time Poland, that he recharged from local electricity.
He says the prototype cost as much as two Ferraris to build, but would cost around 10,000 euros ($12,620) if mass produced, with an extra 4,000 euros for solar panels.
Mr Palmer said he now plans to return home: "I promised my mother to be back before Christmas."
But next year, he plans to arrange a trip with six vehicles around the world in 80 days drawing power from sources such as hydro, geothermal and wind energy.
