On 10 May 2024 at 17h:07 UT, the simultaneous arrival of several solar coronal mass ejections (CME) generated the strongest geomagnetic storm of the last twenty years with a minimum Dst = -412 nT, usually referred to as the Mother’s Day event. This event generated nice auroras visible in many countries of the world at unusual lower latitudes. We showed that this geomagnetic storm generated for the first time the formation of four electron belts remaining during more than one month after the event. This was never observed before. Moreover, an exceptional injection of protons in the South Atlantic Anomaly was also observed. The ionosphere also showed unusual features: The ionization of the upper atmosphere shortly increased at the arrival of the CME but was followed by a fast decrease at all latitudes. The ionization remained very low for more than a full day. The sudden recovery in the middle of the second day on 12 May was very unusual. The ozone concentration in the thermosphere and mesosphere was also observed to decrease during several days.