We are deeply saddened by the current events in Ukraine. Modern society in general and science in particular thrive on free exchange - across borders. Only in such an exchange will we be able to master the challenges of the present. As an institution that has been organising and hosting interdisciplinary and international research groups for over 50 years, we are horrified to see how, with the attack on Ukraine, the very foundations of our beliefs are also being attacked. Above all, our thoughts are with the people on site as well as with all those who suffer.