GermaNet is regarded to be a valuable resource for many German NLP applications, corpus research, and teaching. This demo presents three GUI-based tools meant to facilitate the exploration of and navigation through GermaNet. The GermaNet Explorer exhibits various retrieval, sort, filter and visualization functions for words/synsets and also provides an insight into the modeling of GermaNets semantic relations as well as its representation as a graph. The GermaNet-Measure-API and GermaNet Pathfinder offer methods for the calculation of semantic relatedness based on GermaNet as a resource and the visualization of (semantic) paths between words/synsets. The GermaNet-Measure-API furthermore features a flexible interface, which facilitates the integration of all relatedness measures provided into user-defined applications. We have already used the three tools in our research on thematic chaining and thematic indexing, as a tool for the manual annotation of lexical chains, and as a resource in our courses on corpus linguistics and semantics.