Building of the high government authorities of the Russian Empire consists of two blocks, joined by a high arch of extremely solemn forms, decorated with allegoric sculptures. fronts of the extended construction form the gala aspect of the square. The motif of stanzas with decastyle Corinthian porticos is repeated in the middle of each block. The rounded corner of Synod giving on the Neva river is also marked by a colonnade. The ensemble of Senate and Synod is the last big project of the architect Carlo Rossi.