Photo taken on June 3, 2019 shows the Kazan Cathedral in St. Petersburg, Russia. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Photo taken on June 4, 2019 shows buildings by the Neva river in St. Petersburg, Russia. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Photo taken on June 3, 2019 shows the Neva river in St. Petersburg, Russia. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Tourists pose for pictures at Dvortsovaya Square in St. Petersburg, Russia, June 4, 2019. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Tourists enjoy themselves at Dvortsovaya Square in St. Petersburg, Russia, June 4, 2019. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Tourists line up to visit the State Hermitage Museum in St. Petersburg, Russia, June 4, 2019. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Photo taken on June 4, 2019 shows the Cruiser "Aurora" in St. Petersburg, Russia. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Photo taken on June 3, 2019 shows Saint Petersburg Stadium in St. Petersburg, Russia. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Photo taken on June 4, 2019 shows the Peter and Paul cathedral in St. Petersburg, Russia. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
Photo taken on June 4, 2019 shows the Admiralty building in St. Petersburg, Russia. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)
People run by the Neva river in St. Petersburg, Russia, June 3, 2019. St. Petersburg is Russia's second largest city. (Xinhua/Sadat)