This is the 2750th most frequent Russian word.
иркутске
"Iркутске" is the prepositional form of "Иркутск," meaning "in Irkutsk," a city in Russia.
In this sentence, 'Иркутске' is used as the prepositional case form of the proper noun 'Иркутск', indicating the location where the action occurred.
Я был в Иркутске прошлым летом.
I was in Irkutsk last summer.
Here, 'Иркутске' again is in the prepositional case, used to describe the location containing the beautiful places.
В Иркутске много красивых мест для посещения.
There are many beautiful places to visit in Irkutsk.
In this sentence, 'Иркутске' is in the prepositional case, used to specify the place where the story happened.