When Armstrong and Aldrin landed on the Moon which nations at the time 
did not inform their citizens of this historical event?
Many Thanks
Mongolia

Hello again, Mongolia!

I've found your answer on a BBC site:

"Aldrin later recalled that among all the talk of peace and
tranquillity he was concerned that the flag would not fall over in
front of the television cameras. The proceedings were relayed to
Collins circling above who was 'probably the only person around
without television coverage'. In fact only four nations on earth,
China, Albania, North Korea, and North Vietnam did not inform their
populations of the landing, while the USSR made the announcement on a
television broadcast some six hours after the event."

BBC: Apollo 11, The First Landing
http://www.bbc.co.uk/dna/h2g2/A429086 

My Google search strategy:

Google Web Search: "landed on the moon" OR "moon landing" "did not inform"
://www.google.com/search?hl=en&q=%22landed+on+the+moon%22+OR+%22moon+landing%22+%22did+not+inform%22

Thanks for a great question! If anything is unclear or incomplete,
please don't hesitate to ask for clarification.

Best regards,
pinkfreud

I did not exspect this very precise answer.!
Many Thanks
Mongolia

Thank you very much for the five stars and the nice tip!

~pinkfreud