In general, one innovative aspect of the subject matter described in this specification can be embodied in methods that include the actions of receiving content of a document that is displayed on a user device; determining, from the content of the document that is displayed on the user device, a factual entity that is related to the content of the document; requesting content of a knowledge panel for the factual entity, wherein the knowledge panel is a user interface element that provides a collection of content related to the factual entity; and receiving the contents of the knowledge panel for contemporaneous display on the user device with the content of the document. Other embodiments of this aspect include corresponding systems, apparatus, and computer programs, configured to perform the actions of the methods, encoded on computer storage devices.