One goal of education for sustainable development is to promote students' abilities in systems thinking in the area of knowledge acquisition. However, there are virtually no empirical results in the extracurricular sector regarding the impact of appropriately designed educational offerings. Therefore, this work raises the question of whether and to what extent educational events frequently attended by school classes at extracurricular learning locations influence students' systems thinking. In the present field study, results were obtained using the assessment tool "Concept Map" as part of an intervention on the topic of the Wadden Sea, which show that learning locations in extracurricular environmental education have the potential to enhance students' system-oriented perspectives.