All language editions of Wikipedia have been banned in China ahead of the sensitive anniversary of the deadly 1989 Tiananmen Square protests.
Previously, the Chinese-language edition of Wikipedia had been blocked, but now other editions of the online, user-generated encyclopedia are also inaccessible in China.
There may be a copy of Wikipedia somewhere on the moon.
"In late April, the Wikimedia Foundation determined that Wikipedia was no longer accessible in China. After closely analysing our internal traffic reports, we can confirm that Wikipedia is now blocked across all language versions", Wikimedia said in a statement.
The Open Observatory of Network Interference (OONI) reports that the original ban was expanded to cover all languages last month.
China has banned online encyclopedia Wikipedia, six years after the platform's founder, Jimmy Wales, refused to comply with China's regulatory demands regarding the site's content. However, Wikimedia Foundation told AFP that it hadn't received any notices regarding the block.
Images can also be considered taboo, he said.
"At the end of the day, the content that really matters is Chinese-language content", said Charlie Smith, the pseudonym of one of the co-founders of Greatfire.org, which tracks online censorship in China.
'When one country, region, or culture can not join the global conversation on Wikipedia, the entire world is poorer, ' Lien adds. "It symbolises the fear that the Chinese authorities have of the truth". June 4 marks thirty years since thousands of pro-democracy student protesters were killed by authorities at Tiananmen Square.