This is the 323rd most frequent Russian word.
городах
The word "городах" is the prepositional plural form of "город" (city) in Russian, meaning "in (the) cities."
The word 'городах' is in the locative case, used to indicate the location where an action or state takes place, in this case, 'in big cities'.
В крупных городах часто много музеев и театров.
In big cities, there are often many museums and theaters.
Here, 'городах' also takes the locative case, specifying the cities where the action occurred.
В некоторых городах сейчас проходили праздничные шествия.
In some cities, festive parades were taking place at that moment.
The usage of 'городах' in this context is descriptive, pointing to the cities located in a particular region.