Wikipedia has long been the place to look up information about all sorts of subjects. In 2012 Wikimedia (the organization behind Wikipedia) started Wikidata: a central storage for the structured data of its Wikimedia sister projects including Wikipedia, Wikivoyage, Wikisource, and others.
WIkidata contains structured data about all subjects covered in Wikipedia and much more. It's freely usable and all the data can be downloaded or queried using SPARQL.
Wikimedia
https://www.wikimedia.org/
Maarten is a network engineer by day and a Wikimedia volunteer by night.
