Considered one of the finest squares in the world and certainly the prime attraction of Venice, the 500 feet (180 m) long and 230 feet (70 m) wide Piazza San Marco is the only piazza in Venice, since the other squares of the city are known as campi or fields.

Established during the ninth century, and attained its current size and shape in 1177, it was paved another hundred years later. Lying before the five arched portals of Saint Mark’s Basilica, it was aptly described by Napoleon as the finest drawing room in Europe. Since the days of the Republic, when it was a market, life in Venice has revolved around the piazza as the centre of civic and religious life. It is surrounded on three sides by the stately arcades of public buildings, with the San Marco’s Basilica with its domes and arches on the fourth side, along with the tall St Mark’s Campanile or the Basilica's bell tower, the Doge's Palace, and the Loggetta del Sansovino at the foot of the Campanile. The northern and southern wings of the square are bifurcated by the buildings of the Old Procurators’ Offices and the New Procurators’ Offices, which now house the fashionable shops and elegant cafes, inviting customers to their open-air tables. At the basilica end of the Old Procurators’ building stands the Torre dell' Orologio or St Mark’s Clock tower where the hours are struck by two Moorish figures made of bronze.

One of the most important attractions of the Piazza San Marco is the Patriarchal Cathedral Basilica of Saint Mark, popularly known as Saint Mark’s Basilica, located at the eastern end of the Piazza San Marco, adjacent and connected to the Doge’s Palace, the seat of the supreme authority of the former Venetian Republic.

Although the first building of St Mark, consecrated in 832, was founded as a ministerial structure to house the remains of St Mark, the construction of the present Saint Mark’s Basilica was probably completed in 1071. A great part of the piazza includes the whole of its western façade, decorated with great arches and marble works, the Romanesque carvings around the central doorway and, the four horses which preside over the whole piazza are symbols of the pride and power of Venice. Four hundred years later, Napoleon removed and shipped the majestic horses to Paris, after he had conquered Venice, which were subsequently returned in 1815.

Today, the originals are kept in the museum of the Basilica, and replicas were placed in their place. The interior of the basilica is covered in ethereal and luminous gold mosaics, the magnificent golden Byzantine retable known as the Pala d'Oro, the marble floors, in addition to several enamels depicting various saints.

Standing by the side of the iconic building of the Cathedral Basilica of Saint Mark, the big pink building of the Doge’s Palace, topped with a series of white pinnacles, creates one of the most popular and fascinating scenes of the Piazza San Marco, as well as the City of Venice. The airy design and soft colour of the palace appear to be a refreshing change from the series of domes, arches, and the mosaic of the basilica’s gorgeous façade. One of the highlights of the palace is the incredible 175.5 feet (53.5 m) long and 82 feet (25 m) wide Higher Council Hall or Sala del Maggior Consiglio, decorated with the longest canvas painting of the world, Il Paradiso, the monumental oil painting by Tintoretto. Apart from that, it has many more paintings by other great artists, like Bellini, Titian, Carpaccio, and Veronese.

The Bridge of Sighs, spanning the Rio di Palazzo, also known as the Palace River, is the only bridge in the world that connects a palace and a prison. Designed by Antonio Contino and constructed in 1614, in the style of the Italian Renaissance, the 36 feet (11 m) wide highly ornamented bridge initially served as an enclosed corridor to take the prisoners from the halls of the courts of Pałaso Dogal or the Doge’s Palace to the Prigioni Nuove, the new prison that was built across the canal in the late 16th century. Traditionally named Ponte dei Sospiri, it eventually became popularly known as the Bridge of Sighs, based on the sighs of the condemned prisoners as they caught their brief glance of Venice through the tiny windows of the corridor, before being thrown into their cells in the Prigioni Nuove.

Dominating the townscape and soaring above the pinnacles of San Marco, the Campanile, a free-standing and slightly rectangular structure, clad in Venetian red-clay brick, is the massive 324 feet (99 m) tall bell tower of the basilica. Construction of the structure began in the 10th century and was completed in the 12th century. However, its pointed roof and the gilded pinnacle were not added before the 15th century. Unfortunately, it collapsed into the piazza in a heap of rubbles on 14 July 1902, smashing the Loggetta, located at its foot.

The Loggetta was built by Sansovino between 1537 and 1540, for the members of the Great Council to assemble before going into the session. By 1912, the Campanile had been painstakingly rebuilt to its original height, along with the marble Loggetta, rebuilt by using the original stones recovered from the rubbles. Even the four bronze masterpieces of Sansovino were also recovered, which now stand between the twin columns.

Another Venetian icon in the Piazza San Marco is the Torre dell' Orologio or St Mark’s Clock tower, designed and built by Mauro Codussi between 1496 and 1499. Joining the eastern end of the Procuratie Vecchi, the building reflects the Venetian Renaissance architecture. However, its mosaic of gold stars glittering against the blue background and the Lion of St Mark were added much later, in 1755, by Giorgio Massari. The two huge bronze statues on the terrace of the tower, one representing an old man and the other young, who strike the bell to mark the hour, were cast by Paolo Ranieri. Although said to represent shepherds, they are known as the Moors, probably due to the dark patina acquired by the bronze. The bell in the tower, created by Simeone Campanato in 1497, bears his signature. One can climb up the tower to get a closer view of the bronze figures and the bell. The big clock that gives the tower its name was also made by Ranieri and his son. It is located above the archway into the Mercerie leading to the Rialto and besides showing the hour, it also indicates the phases of the moon and the signs of the zodiac.

The Procuratie, the former offices of the Procurators, the chief officials of the Republic, borders the north and south sides of Piazza di San Marco. Later, the Procuratie Vecchie, with arcades all along its façade, was built between 1480 and 1517. However, soon it was felt that even the enlarged Procuratie Vecchie is not big enough and by 1582, the construction of the Procuratie Nuove, designed to harmonize with the earlier one, began on the opposite side of the piazza. The third building that finishes off the end of the piazza, and now known as the Ala Napoleonica, was constructed between 1805 and 1814, by the order of Napoleon, after he proclaimed himself the King of Italy. Today, those buildings house the Museo del Risorgimanto, the Museo Archeologico, and the Museo Civico Correr.