A scientific hour on the topic Geotechnical and Environmental Characterization of Unbound Mixtures of Recycled Concrete Aggregate and Shredded Car Tires was held in the conference hall of the Faculty of Civil Engineering, Architecture, and Geodesy, University of Mostar, on Tuesday, 14 April 2026. The lecture was given by Professor Katarzyna Gabryś, Ph.D., from the Department of Geotechnics at the Institute of Civil Engineering, Warsaw University of Life Sciences (SGGW). The topic of the scientific hour was related to a scientific research project conducted under the OPUS program and funded by the National Science Center in Poland. The main objectives of the project, the research team, international partners, methodology, research plan, as well as ongoing investigations were presented. As part of the scientific hour, a second lecture was given by Professor Katarzyna Markowska-Lech, Ph.D., also from the Department of Geotechnics at the Institute of Civil Engineering, Warsaw University of Life Sciences (SGGW), on the topic: The Structure and Scientific Activity of the Faculty of Civil and Environmental Engineering at the Warsaw University of Life Sciences (SGGW).