Automated knowledge base construction is a long-standing challenge in AI. The goal is to abstract concise representations from various sources of knowledge, such as unstructured documents, web data and knowledge bases. The outcome is a knowledge graph that can be used to enhance downstream applications like search engines and business analytics. Highly accurate and extensive knowledge graphs are the prerequisite to enable machine reasoning and decision making in AI. For example, knowledge base construction was an essential component of the DeepQA system that defeated the human grand-champions at Jeopardy! and has since been a very active research direction as it enables the adaptation of AI solutions to new domains.