There is also certain material, the copyrights of which have expired in one country while still applying in another. The use may however be restricted by issues not related to copyright, though, see Commons:Non-copyright restrictions, and the license may demand some special measures. Wikimedia Commons only accepts free content, that is, images and other media files that are not subject to copyright restrictions which would prevent them being used by anyone, anytime, for any purpose.
If you are a re-user looking for information on how to use Commons content in your own work, see Commons:Reusing content outside Wikimedia. It aims to help uploaders decide whether an image or other media file is acceptable on Wikimedia Commons.
This page gives non-lawyers an overview of complicated copyright laws through an example-based tutorial.
