The ZKM Collection was founded by the ZKM's first director, Heinrich Klotz, in the early 1990s and has been added to ever since. The collection is based on a specific approach to the different art genres and media: whereas painting and sculpture were hermetically sealed off from the new influences of video art and photography which were gradually establishing themselves, the ZKM's collecting activity is distinguished by transcending such traditional genre divisions. While the Museum of Contemporary Art's collection contained artworks of all genres from the very beginning, the Media Museum's collection initially only contained works of interactive media art most of which were produced in-house. Over 500 international guest artists produced a vast number of works at the ZKM, which entered the ZKM Collection after their initial presentation in Karlsruhe. Consequently, the ZKM has one of the largest collections of media art in the world, extending back to the beginning of video art, electronic installations, and holography. In addition to these there is the collection of approximately 1,200 art videos and 13,800 audio tracks, which are not stored in the museum, but can be accessed via the ZKM | Media Library.