IAGA: a major role in understanding our magnetic planet

Abstract. Throughout the International Union of Geodesyand Geophysics's (IUGG's) centennialanniversary, the International Association of Geomagnetism and Aeronomyis holding a series of activities to underline the ground-breaking facts in the area of geomagnetism and aeronomy. Over 100 years, the history of these research fields is rich, and here we present a short tour through some of the International Association of Geomagnetism and Aeronomy's (IAGA's) major achievements. Starting with the scientific landscape before IAGA, through its foundation until the present, we review the research and achievements considering its complexity and variability, from geodynamo up to the Sun and outer space. While a number of the achievements were accomplished with direct IAGA involvement, the others represent the most important benchmarks of geomagnetism and aeronomystudies. In summary, IAGA is an important and active association with a long and rich history and prospective future.