In this talk, I will present our recent work in the area ofknowledge bases. It covers 4 areas of research around ontologies andknowledge bases: The first area is the construction of the YAGOknowledge base. YAGO is now mulitlingual, and has grown into a largerproject at the Max Planck Institute for Informatics and TélécomParisTech. The second area is the alignment of knowledge bases. Thisincludes the alignment of classes, instances, and relations acrossknowledge bases. The third area is rule mining. Our project findssemantic correlations in the form of Horn rules in the knowledge base.I will also talk about watermarking approaches to trace the provenanceof ontological data. Finally, I will show applications of theknowledge base for mining news corpora.