Come and find out all about hydrogen, and how it can power London's low carbon future at this special exhibition at City Hall.
Hydrogen is the most common element in the universe. It's 14 times lighter than air, and is found in every living thing on earth.
Several countries are now looking at hydrogen as a way to generate power for transport like cars, buses, scooters, boats and planes, and for buildings.
Here in London, the Mayor is supporting the Hydrogen London partnership to help London take full advantage of hydrogen fuel cell technology and reduce our future CO2 emissions.