They are both 1 exact the cathedral.The Peter and Paul Cathedral is a Russian Orthodox cathedral located inside the Peter and Paul Fortress in St. Petersburg, Russia.

it is 450 Rubles, but if you are with a tour company like SPB it is included

двс(доброго времени суток)реставрационные работы закончены)) вход бесплатный ))!там идут службы он действующий !венчают, крестят, отпевают ,ведут покаяние и читают молитвы разные соответственно канонам православным праздникам ))

the cathedral is under renovation, but only the outside. I've been inside in july 2015 as well as in january 2016. last summer the domes were not covered with scaffolding yet. anyway, the cathedral is still working and thus holding services. at least in january it still did. worth a look inside, indeed. the murals are beautiful, in old-russian style even though the cathedral is about a hundred years of age only. I suppose that the platform on top of the cathedral will be closed at the moment as the scaffolding will limit the view.

так же как и в любом другом православном храме вы можете обвенчаться по личной договоренности о времени и украшений службы венчания )) у администрации собора ))