Nuclear fusion - the power that fuels the sun - is a promising approach to obtaining a CO2-free, safe and continuous energy source. For decades researchers have tried to make nuclear fusion happen on Earth, but the ideal fusion reactor does not exist… yet. In this year’s Hendrik de Waard Lecture, Josefine Proll will share recent developments in nuclear fusion. She will explain why we need to use strong donut-shaped magnetic fields to harness the million-degrees hot fusion plasma and prevent it from melting the reactor wall. Also, she will show how clever shaping of the magnetic fields can be used to tackle remaining challenges like turbulence and the fusion fuel and loss of heat - a promising development in nuclear fusion!