After 50 years of volcanic quiescence, Cumbre Vieja volcano erupted at its western flank on 10 September 2021. The eruption lasted for three months and was the largest one by volume on La Palma, and the second of the entire Canary Islands, in historic times. It was also the most destructive, with consequences for La Palma not yet foreseeable. The pre-, syn-, and post-eruptive phases were fully monitored with modern instrumentation, providing an unusually clear picture of magma movement before and during the eruption. In this talk Andreas Klügel reviews the eruption and its predecessors, and compares geophysical observations to those obtained by petrological studies of erupted lavas. He discusses how the combined data improve our understanding of the magmatic plumbing system of the volcano. The talk also includes some personal impressions from a one-week visit to the erupting volcano.