The Ducal Palace (Doge's Palace, Palazzo Ducale, Dogenpalast) in Venice is a masterpiece of Gothic architecture, and it has been made over the centuries, but the wing facing the St. Mark's basin (as shown in the photo) is the oldest and was built from 1340 onward under Doge Bartolomeo Gradenigo (1339-1343). It is interesting to note that although the word, palace or "palazzo" in Italian" was used, the office of Doge was not hereditary, but it was an elected office throughout its more than one thousand years' of history.
The essence of the façade structure is the portico with big columns at the top forming a pointed arch and the loggia, an open-sided gallery, supported by columns, also forming a pointed arch but with inflection and on the top a quatrefoil frieze. Above the loggia, there is a wall made of colored Verona marbles, white and pink, making a pattern. The marble pattern is better seen in my photo of its west façade.
For additional information on its history and the structure, see Musei Civici Veneziani.