Henri Astier assesses the risks from the rise and rise of France’s online far right.

How slums are offering low-tech smart solutions to common city problems.

Solar energy start-up Insolar installs solar panels on key buildings in the Santa Marta favela.

A Silicon Valley start-up develops an app that provides on-demand help to gardeners.

Over the next three weeks, about 100 people will travel in a prototype vehicle on a two-mile route.

The BBC’s Pallab Ghosh has been finding out about a filter made from graphene that can turn salt water into drinking water.