The Walls of Iraklio were constructed during the Venetian period. The construction started in 1462 and it was completed in the middle of the 16th century. They are characterised as the top fortifications of Europe. The circuit of the Walls was about 5 kilometres and they were surrounded by a deep dike full of water. In the past, in order to enter the city, people had to pass through one of the four gates: the Gate of St. George, the Gate of Jesus, the Gate of Pantocratoras or the Gate of Bethlehem. The Gates were protected by the bastions: the Bastion of Martinengo, where lies the tomb of Nikos Kazantzakis, the Bastion of Bethlehem, the Bastion of Pantocratoras, the Bastion of Jesus, the Bastion of St. Andrew, the Vitturi Bastion and the Bastion "Sabbionara" (of the sand).