This is the 11446th most frequent Russian word.
довоенной
"Довоенной" means "pre-war" in English.
In this sentence, "довоенной" is an adjective describing the noun "эпохи." It means "pre-war" and refers to the time before a specific war.
Музей хранил артефакты довоенной эпохи.
The museum preserved artifacts from the pre-war era.
Here, "довоенной" modifies the noun "жизни," emphasizing events or conditions existing prior to the war.
Её рассказы были полны воспоминаний о довоенной жизни.
Her stories were full of memories about life before the war.
In this usage, "довоенной" describes "Москвы" in a possessive or descriptive manner, implying the state of architecture in Moscow as it was before the war.