Title: The fortress
Subjects: Revolutionaries, Petropavlovskai︠a︡ krepostʹ (Saint Petersburg, Russia), Petropavlovskai͡a krepostʹ (Saint Petersburg, Russia)
Places: Petropavlovskai︠a︡ krepostʹ (Saint Petersburg, Russia), Russia) Petropavlovskai︠a︡ krepostʹ (Saint Petersburg, Soviet Union