In this series of articles, I will introduce the reader to the scienceof ethology, somewhat indirectly by describing simpleexperiments, both old and new, designed to understand howand why animals behave the way they do. My emphasis willbe on the design of the experiments and my goal will be tomotivate readers not only to think about the design but alsoto come up with alternatives and improvements. Motivatedreaders can indeed replicate some of these experiments evenif they end up replacing the study animal or the behaviours ofinterest with their own favourite choices. In the first part ofthe series, I describe how Niko Tinbergen – Nobel Laureateand one of the founding fathers of ethology (the science of animalbehaviour) – designed remarkably simple experimentsto successfully understand how digger wasps find their ownnests in a complex habitat also consisting nests built by otherwasps.