Wikipedia is the largest wiki on the planet, with several million articles available in English and several million more in dozens of available languages.
For once, a site that recognizes the importance of third-party backups! They have a main downloads page from which you can get XML dumps from individual wikis (Wikimedia Foundation hosts more than 800 wikis: Wikipedias, Wiktionaries, Wikinews, Wikisources, Wikibooks, Wikiquotes, Wikiversities, Wikispecies, Wikimedia Commons, Wikivoyage, Wikidata).
- WikiTeam script to download Wikipedia dumps from download.wikimedia.org
You can download all the articles of the English Wikipedia (with complete edit history) in an unique file (compressed in 7zip format) from here (ATTENTION: 31 GB! Unpacked it expands up to 5.2 TB. Direct link: pages-meta-history.xml.7z 2010-01-30).
Some Wikipedia dumps in the Internet Archive.
There is no current public backup for images uploaded to Wikimedia Commons which has about 10 million images and other media files uploaded on its services.
- official backups site
- some incomplete old dumps, English Wikipedia mainly
- old wikipedia backups discovered (announcement)
- Internet Archive results: http://www.archive.org/search.php?query=wikipedia%20dumps
Transferring to IA
Hydriz is currently transferring the dumps of all Wikimedia projects into the Internet Archive. Wikimedia itself has provided resources to me for transferring these dumps to the Internet Archive. Do see the collection here.
Stable, but they seriously use a lot of tactics to get donations.
- Wikimedia Commons
- WikiTravel - Not a Wikimedia project, but its content was forked to create WMF-hosted rival Wikivoyage.