The Hans Cloos Lecture (HCL) 2024 was delivered by the first author Niek Rengers, in an abridged version, during the opening session of the 4th EurEngeo conference of the International Association for Engineering Geology and the Environment (IAEG), in Dubrovnik, Croatia, October 10th, 2024. Niek Rengers looks back on his personal involvement in more than 60 years of study, teaching, and research in engineering geology, and, with the team of authors, they focus on the main activities of the Dutch engineering geological community during the five decades since 1973. A brief description is given of the challenges of civil engineering over the past 2,000 years in once marshy land, below high tide sea level, with soft soils, and subject to flooding by the sea and the main rivers Rhine and Meuse. Dutch engineers tackled these challenges by dike construction, land reclamation in polders, and the use of pile foundations for building on soft soils. They so gathered over the ages a wealth of practical experience with soft soils. Based on this practical expertise, Dutch engineers developed a sound basis for theoretical and experimental Soil Mechanics. However, in the early seventies, it became clear that a thorough knowledge of the geological structure of the underground was indispensable for adequate geotechnical analysis and modelling. This led to the founding of the Dutch National Group of the IAEG in 1974. Since 1972 the International Institute for Aerospace Surveys and Earth Sciences (ITC) offered full year university level courses in engineering geology. The Mining Engineering faculty of the Technical University Delft followed in 1975. In close cooperation and with extensive staff exchange, both institutions have further developed engineering geological education and research programs leading to MSc and PhD degrees. A summary description is given of these developments during the last 5 decades.