From the capital of Mongolia (population 1,000,000).
Can't confirm the date as the cancel is so weak and smudged, just going by the dated note on the card. Postal use from Genghis Khan territory!
Still haven't figured out what that round building is (museum?, ice skating arena?). Here is a picture taken from in from of the State Department Store on Peace Ave looking that way, you can see the building's roof in the background.