надо поставить определенный артикль the где это нужно. sometimes... ST Petersburg is called the second capital of...Russian

     Вставив где необходимо определенный артикль, мы получим следующий текст:

     Sometimes St Petersburg is called the second capital of the Russian Federation. Tourists from different countries come to St Petersburg to visit its famous museums and to walk along Nevsky Prospect. You can see tourists from France and the United States, China and Great Britain in Dvortsovaya Square. There are also lots of Russian tourists from Krasnodar and Vladivostok, from Kaliningrad and Moscow. Would you like to visit St Petersburg some day?