Lantern slide labeled Petrograd. In 1787-1792 Quarenghi designed and built a wing along the Winter Canal with the Raphael Loggias to replicate the loggia in the Apostolic Palace in Rome designed by Donato Bramante and frescoed by Raphael. The loggias in Saint Petersburg were adorned with copies of Vatican frescoes painted by Cristopher Unterberger and his workshop in the 1780s.

In the reign of Catherine II a grand palace ensemble was created that served as an official state residence, a storehouse of art treasures, and also as a home where the Russian Empress spent her private life. Out of six buildings of the main palace (now museum) complex, four, namely the Winter Palace, Small Hermitage, Old Hermitage and New Hermitage, are partially open to the public. The other two are Hermitage Theatre and the Reserve House. Next to the Winter Palace are Fel'ten's Large or Old Hermitage (1771-1787), Jean-Baptiste-Michel Vallen de la Motte's Small Hermitage (1764-1767) and Giacomo Quarenghi's Hermitage Theatre (1783-1787). The 19th century saw the construction of the Hermitage Museum at the back of the Winter Palace--now known as the New Hermitage, since the museum has expanded to fill the whole imperial palace complex--where the cream of the imperial collection could be shown to the public; it opened its doors in 1852. This was the first Russian public museum. The tradition of collecting works of art which began in Catherine's time had now become an element of state policy.