The fortified enclosure of the Venetian Chandakas of the 15th century, which is still preserved today, is one of the most significant monuments of its kind in the whole Mediterranean basin.
Triangular in shape, with its base at the sea, the mighty enceinte has a perimeter of about 5.5 kilometres. The hallmark of the defensive layout are the bastions, linked by curtain walls decorated at many points by escutcheons and the lion of St. Mark, symbol of Venetian omnipotence. The gates in the enceinte, which served to link the town to the countryside, still stand as important architectural monuments.
To this day, the walls that withstood the Ottoman siege in the mid-17th century mark out the boundary of the old town.

The bastion heart shaped in plan with an acute angle, has two "piazza bassa" and one cavalier. It defines the southeast and the highest part of the fortification. Its name is due to Gabriele Tadini Martinego (1520) who started the construction of a circular tower at the place of the later bastion. It was one of the strongest bastions (the others were that of Pantocratora and that of Vittouri) which also suffered the main attack and most of the bombardment from the Turks.
On the top of the bastion itself there was made a cavalier (which looks like a smaller bastion), whose main purpose was the better defense and control of the area around the bastion.

The grave of Nikos Kazantzakis, the famous Cretan writer, is situated on the highest point of the Venetian fortification at the Martinego cavalier. The inscription by the wooden cross reads: " I hope for nothing. I fear nothing. I am free ", a phrase taken from "The Odyssey" which Kazantzakis considered as one of his most significant works.

The playgrounds of the Academy of the local football team "Ergotelis" are located today on the main bastion and in the ditch around the bastion are the botanical gardens of the city.