Hi Elena, it sounds like you really enjoyed your holiday. My impression was that the Belorussian language was the same as Russian. I'd love to see photos of the castles and Minsk.

Беларусь land.

In this During the May vacations I tavelled to Belarus. This is a country near that neighbours Russia. It is a wonderful country place to visit! There are a lot (many) of forests and lakes - so it has a good ecology [your meaning is clear, but it might be better to say "so the environment is pristine/healthy/wonderful/natural]. I was in Minsk and two of the castles near it.
Minsk is a very clean and green town - but its the buildings in the town centre are from the middle of the 20th century XX ("such as like South Korea" - said my friend)." Or a Tverskaya in Moscow" [not reported speech, so do not use ""] - I think.
The prices in Belarus are so very cheap low. The ways quality of life (?) - are is so good [instead, use fantastic/amazing etc]. They use the Russian language in the big cities.

So - now it is my favourite country now (together with Russia and Italy).

I specially like the Belarussian castles and my next story will be about them