In this week's edition a ball of energy ten times the temperature of the sun's core is created at an Oxford laboratory. The aim of this pioneering research is to produce unlimited clean electricity through nuclear fusion, as opposed to the present system of nuclear fission, which produces long-term radioactive waste.

Also tonight the reasons why 1,000-year-old pagodas in Japan remain standing during earthquakes, and how the secrets of ancient builders are being applied to the design of a new skyscraper in Tokyo. Plus a spy plane being developed by the US military that's so small it can sit in the palm of the hand.
Presented by Philippa Forrester and Jez Nelson, with reports from Peter Snow, Craig Doyle and Anya Sitaram.
Producer Liz Tucker; Editor Saul Nasse
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