The world's first ship able to travel the seas powered by hydrogen produced directly onboard has docked in London.
Already 18,000 miles into its six-year-long journey around the globe, the zero-emission Energy Observer is being moored by Tower Bridge for 10 days to celebrate the end of the European leg of its voyage.
The 30-metre-long catamaran uses electricity from solar panels to electrolyse seawater, in order to generate hydrogen and oxygen.
The oxygen is then released into the atmosphere, while the hydrogen is burned to generate power, emitting only water vapour as it does so.
Along with direct power from the panels and with the help of modern sail structures, the clean gas allows the ship to travel at speeds of up to seven knots.
Its creators hope it can demonstrate that the shipping sector can be decarbonised, in order to tackle the growing threat of climate change.
Jon Hunt, Manager of Alternative Fuels at Toyota, said: "What we're showing here is again, back to the fact that it [hydrogen] can be used in a real environment, a very harsh environment, safely and practically and durably."