It has been a great pleasure to have hosted Dr. Olumuyiwa Adegun. A Senior Lecturer in the Department of Architecture, Federal University of Technology, Akure, Nigeria, Dr. Adegun has been Visiting Researcher within the framework of DAAD ClimapAfrica Programme at our Chair. His lecture on „Slum Upgrading and environmentally sustainable interventions in sub-Sahara Africa“ was well received and an eye-opening experience, especially for our IUSD students. Alas, due to the covid pandemic there could not have been a farewell party, but we are looking forward to further mutual visits and our continuing fruitful co-operation with Dr. Adegun. A joint publication on heat stress in the context of informal settlements in Africa is in process.