The Piazzetta di San Marco is (strictly speaking) not part of the Piazza but an adjoining open space connecting the south side of the Piazza to the waterway of the lagoon. The Piazzetta lies between the Doge's Palace on the east and Jacopo Sansovino's Libreria which holds the Biblioteca Marciana on the west.
Nearer the Cana, there are two columns brought in the 12th century from Constantinople. Originally, there was also a third one, which fell into the lagoon during its instalation. At the top of one of them there is a statue of St Theodore (first patron of Venice) and a dragon. The other one is topped with The Lion of Saint Mark, representing the evangelist in the form of a winged lion. The sculptures are later additions.
The area served not only as a ceremonial entrance to the city center but was also used for executions and gambling in the heyday of the Venetian Republic.
Inside of The Piazzetta di San Marco you can also find: National Library of St Mark's in Venice ,