The Iron Man star tells us how he wants to help tackle the climate crisis. Plus, how small investors on a Reddit forum took on Wall Street and won - for now at least. And have your shopping habits changed in the last year? A retail expert tells us how the pandemic has shown which brands have managed to adapt to the online revolution. Presented by Rory Cellan-Jones with BBC senior tech reporter Jane Wakefield. Produced by Jat Gill.

(Image: Robert Downey Jr. against a pink and yellow gradient background, Credit: Getty Images).