Learn French: Dans ce pays, il n'y a pas de montagnes. - In this country, there are no mountains.

This is a special rule for negative sentences! In the positive sentence, you would say il y a des montagnes (there are mountains). But after negative expressions like il n'y a pas, the plural article des always changes to de.

How exactly do you build the negative for il y a?

Il y a means "there is" or "there are". To make it negative, you put the two parts of the negative, ne and pas, around the y a part. Because y acts as a vowel here, ne drops its 'e' and becomes n', giving us il n'y a pas.

Why does pays have an 's' at the end if the sentence says "this country" in the singular?

Some French words naturally end in 's' even when there is only one of them. Pays (country) is one of those words! It stays exactly the same in singular and plural. You can tell it means just one country here because it is paired with ce (this).

Why use ce for "this" instead of cet or cette?