2019 was the “year 1” of the Astroparticle Physics division, but not the first year of astroparticle physics at DESY. Activi-ties in Zeuthen (then in the German Democratic Republic) started in the late 1980s with the participation of the Institute of High-Energy Physics (IfH) in a Russian experiment to detect astrophysical neutrinos in Lake Baikal. In 1991, the institute – and with it its astroparticle physics activity – became the Zeuthen branch of DESY. The Baikal neutrino telescope led to the DESY involvement in the AMANDA and IceCube neutrino observatories at the South Pole, the dis-covery of astrophysical neutrinos (breakthrough of the year 2013) and eventually the identification of the first source of a 290 TeV neutrino, along with many exciting results on neu-trino properties, oscillation pattern and limits on potential source populations.
