This is the 3936th most frequent Swedish word.
ländernas
"Of the countries."
"Ländernas" is the possessive form, meaning "the countries'", showing ownership.
Ländernas kultur är mycket olik.
The countries' cultures are very different.
Here, "ländernas" is used to indicate possession, referring to the capitals of the countries.
Vi ska besöka ländernas huvudstäder.
We are going to visit the countries' capitals.
"Ländernas" signifies the historical background belonging individually to the countries, expressing possession in this context.