Here is a link to an interesting post about how you can use frequent flyer miles to fly to Ulaanbaatar, the capital city of Mongolia.
I was able to use U.S. Air miles in 2013 to fly from Beijing to Ulaanbatar, but that airline has since disappeared and the deal is no longer available.
I found Mongolia to be an interesting place to visit. The government is very friendly to America. The Mongolian language is written in Cyrillic (Russian) characters, so I had no idea what the signs meant.
The major exception was an English-language restaurant/bar just across the street from the large government building.
I stumbled across a tour group, and arranged to see the city with the guide the next day. Frankly, there was not a lot to see…a large Soviet-era monument on a hill overlooking the city, a museum, a centuries-old religious site. Perhaps the best part of the tour was the driving around the city and seeing the people and houses.