Teaching Requirements Engineering needs to be a realistic experience. Otherwise the students might not understand the repercussions of failing to gather requirements correctly. While simulated stakeholders are always a feasible option, only real stakeholders offer an authentic experi- ence since only they are impacted by the system that is being specified. In this paper, we present our experiences of cooperating with the non-governmental organization (NGO) Wasserwacht. In a first requirements engineering course, nine graduate students elicited requirements by interviewing a dozen heterogenous stakeholders. In a subsequent bachelor̢۪s project, four undergraduate students continued by implementing the software system based on these requirements. We discuss the authenticity of our requirements engineering setting the influence of the collected requirements on the follow-up implementation project and how the Wasserwacht benefited from this cooperation.