In a decade, the international fusion experiment ITER will start operating in the south of France. This historic experiment will generate up to 500 MW of fusion power and provide a proof of principle for fusion energy. Fusion has the potential to provide a large fraction of our energy for millions of years. Prof. Cowley will describe the scientific progress in fusion – from Sir Arthur Stanley Eddington’s prophetic predictions in 1920 to the remarkable results that have led to ITER. He will outline the challenging physics problems that must be solved to make fusion power a commercial option, and worldwide efforts to find their solution.