The IMU celebrated its centennial in Strasbourg between 27-28 September 2021 with the conference "Mathematics without Borders". The IMU was officially founded on 20 September 1920 in Strasbourg, just prior to the ICM being held there. The conference took place in the same building used for the ICM 1920.
Information regarding the conference can be found here. Both days of the conference were streamed live by Université de Strasbourg and can be watched below.