Wind-powered ships are sailing cargo around the world again to help cut pollution.
Scientists are trying to tap unlikely-sounding energy sources - like the leaves on trees.
A clever way to provide life-saving oxygen
How sport can change the lives of young people from some of the toughest backgrounds.
How blockchain could solve some of the world’s problems.
We visit farmers growing lettuce, herbs and strawberries indoors in the middle of cities
How sound barriers and noise sensors are helping to make the planet more peaceful
Would robot shuttles, buses on demand and free rides persuade you to ditch your car?
It has taken 40 years, but this man has regrown a patch of rainforest in the Amazon
How human sewage is being recycled to recover a valuable chemical