Mongolia is a country with the most beautiful nature in the world.= Mongolia is one of the countries with the most beautiful natural landscapes
There, you can see horses and camels living in nature.= living freely in the wild
At night, you can see the beautiful milky way.= Milky Way

You did a great job describing Mongolia's beauty in a simple and vivid way! The idea of animals living freely and the Milky Way at night gives the reader a peaceful image. Well done~