  Knowledge Graphs are an emerging form of knowledge representation. While
Google coined the term Knowledge Graph first and promoted it as a means to
improve their search results, they are used in many applications today. In a
knowledge graph, entities in the real world and/or a business domain (e.g.,
people, places, or events) are represented as nodes, which are connected by
edges representing the relations between those entities. While companies such
as Google, Microsoft, and Facebook have their own, non-public knowledge graphs,
there is also a larger body of publicly available knowledge graphs, such as
DBpedia or Wikidata. In this chapter, we provide an overview and comparison of
those publicly available knowledge graphs, and give insights into their
contents, size, coverage, and overlap.
