 This is Wikipedia. It is illustrated with many images. Images that are collected on another wiki. Wikimedia Commons, a sister project of Wikipedia. Wikimedia Commons is a media repository with tens of millions of files. A lot of these are made and collected by Wikimedia volunteers. Images around the world also partner with galleries, libraries, archives and museums. Many files are contributed through these partnerships. Just like on Wikipedia, the files and comments are free to be reused by anyone. You often see them as illustrations on various websites. Now, how do you make more than 50 million free files useful for as many people as possible? How do you make sure that anyone in the world can find an image they need, no matter which language they speak? The answer is structured data on commons. Structured data is information about a file that is easy to understand by humans, but is also machine-readable, easy to understand and processed by computers. This is where Wikidata comes into play, Wikimedia's free knowledge base. It contains data items or entities about almost anything in the world. Each file on Wikimedia Commons can now be described with entities from Wikidata. Unique identifiers help to distinguish different things even if they have the same name. This image shows a kiwi and you point it to the Wikidata entry for the kiwi fruit. This kiwi is not a New Zealander and not a flightless bird. All Wikidata entities are multilingual, so it doesn't matter in which language you search. These entities are also linked data. Wikidata describes relationships between things in the world. So you will be able to find photos of foods named after women and of different kinds of cabbage rolls from cuisines around the world. Concepts from Wikidata are also linked to other databases. For instance, the Library of Congress, iNaturalist and the Internet Movie Database. Many of these databases link back to Wikidata as well. Structured data is already part of Twitter bots, museum timelines and tagging games. As a software developer, you can freely take this machine-readable, multilingual and linked data and use it in all kinds of applications. And most of all, anyone in the world can now search for files on Wikimedia Commons in their own language. Help by contributing free files and structured data to Wikimedia Commons yourself to make more files more useful to more people and more machines.