Surrounding the old city of Dubrovnik, the walls are part of ancient fortification of the city. The walls dating back to 10th century were built to protect against the sea invasions from the south east. The walls were fortified during the period 14th century and 17th century, considered as the golden age of Dubrovnik. The last fortification was carried out in 17th century, to protect it from the attacks of Ottomans; the same structure is preserved till date. The double layered walls are up to 6 m thick and around 4 to 6 m in height. Out of the total length of 2 km, most of the wall parts are land walls and some of them are seawalls. The land walls at certain point reach the height of 25 m whereas seawalls are relatively smaller as they were built on top of higher cliffs. The city harbour constructed in the 15th century is encircled by the walls. The best way to explore the ancient city walls is to hike the entire length of the walls. Admire the majesty of the Old Town and the walls incorporating towers, gates, fortresses and bastions. The awe-inspiring view of the Adriatic Sea from the top of the walls is worth the walk.