Everything is in flux. For example, the population of countries and cities is constantly changing. Staying up to date, for example with Wikipedia authors, is a real challenge. Until now, they have had to manually insert changes into their contributions. The Wikidata project is building a freely usable database for information that can also be read by machines. With the help of this database, digital reference tools such as Wikipedia will be able to be updated automatically. Moreover data can be combined freely. For example, a list of the largest cities with a woman mayor could be created with just a few clicks of the mouse.