Start your walk through the historical center of St. Petersburg on the Art Square in front of the Russian Museum. It will take at least 2-3 hours to visit the museum itself, so leave this visit until the next time. This time, just take a walk around the Mikhailovsky Garden, and also see the Cathedral of the Savior on Spilled Blood. Be sure to step inside to see the masterpieces of Byzantine mosaics.
Then return along the Griboyedov Canal to Nevsky Prospekt to see the Kazan Cathedral with its huge colonnade. The Griboyedov Canal and Nevsky Prospekt are also great sights of St. Petersburg. Walk to the Bank Bridge near the cathedral. This is the most famous bridge on the canals of St. Petersburg.
Go along Nevsky Prospekt to the city center. Along the way, you can see the Stroganov Palace on the Moika River, and then go through the Arch of the General Staff to the Palace Square. The famous Hermitage Museum is located here. It will take even more time to visit it, so just take a walk around the Palace Square, see the canals of St. Petersburg near it, and then go to the Neva Embankment. Here you will see the spire of the Peter and Paul Fortress, which is a symbol of St. Petersburg.
On the Neva Embankment, go past the Admiralty to St. Isaac's Cathedral. Here you will see another symbol of St. Petersburg - a monument to the founder of the city, Emperor Peter I. Go inside St. Isaac's Cathedral, and then climb its colonnade to see the historic center of the city from a height.