Defensive wall

A defensive wall is a fortification usually used to protect a city, town or other settlement from potential aggressors. In ancient to modern times, they were used to enclose settlements. Generally, these are referred to as city walls or town walls, although there were also walls, such as the Great Wall of China, Walls of Benin, Hadrian's Wall, Anastasian Wall, the Cyclopean Wall Rajgir[1] and the metaphorical Atlantic Wall, which extended far beyond the borders of a city and were used to enclose regions or mark territorial boundaries. In mountainous terrain, defensive walls such as letzis were used in combination with castles to seal valleys from potential attack. Beyond their defensive utility, many walls also had important symbolic functions – representing the status and independence of the communities they embraced.

Existing ancient walls are almost always masonry structures, although brick and timber-built variants are also known. Depending on the topography of the area surrounding the city or the settlement the wall is intended to protect, elements of the terrain such as rivers or coastlines may be incorporated in order to make the wall more effective.

Walls may only be crossed by entering the appropriate city gate and are often supplemented with towers. The practice of building these massive walls, though having its origins in prehistory, was refined during the rise of city-states, and energetic wall-building continued into the medieval period and beyond in certain parts of Europe.

Simpler defensive walls of earth or stone, thrown up around hillforts, ringworks, early castles and the like, tend to be referred to as ramparts or banks.

History

From very early history to modern times, walls have been a near necessity for every city. Uruk in ancient Sumer (Mesopotamia) is one of the world's oldest known walled cities. Before that, the proto-city of Jericho in the West Bank in Palestine had a wall surrounding it as early as the 8th millennium BC.

The Assyrians deployed large labour forces to build new palaces, temples and defensive walls.[2]

Some settlements in the Indus Valley Civilization were also fortified. By about 3500 BC, hundreds of small farming villages dotted the Indus floodplain. Many of these settlements had fortifications and planned streets. The stone and mud brick houses of Kot Diji were clustered behind massive stone flood dykes and defensive walls, for neighboring communities quarreled constantly about the control of prime agricultural land.[3] Mundigak (c. 2500 BC) in present-day south-east Afghanistan has defensive walls and square bastions of sun dried bricks.[4]

Babylon was one of the most famous cities of the ancient world, especially as a result of the building program of Nebuchadnezzar, who expanded the walls and built the Ishtar Gate.

Exceptions were few, but neither ancient Sparta nor ancient Rome had walls for a long time, choosing to rely on their militaries for defense instead. Initially, these fortifications were simple constructions of wood and earth, which were later replaced by mixed constructions of stones piled on top of each other without mortar.

In Central Europe, the Celts built large fortified settlements which the Romans called oppida, whose walls seem partially influenced by those built in the Mediterranean. The fortifications were continuously expanded and improved.

In ancient Greece, large stone walls had been built in Mycenaean Greece, such as the ancient site of Mycenae (famous for the huge stone blocks of its 'cyclopean' walls). In classical era Greece, the city of Athens built a long set of parallel stone walls called the Long Walls that reached their guarded seaport at Piraeus.

Large rammed earth walls were built in ancient China since the Shang Dynasty (c. 1600–1050 BC), as the capital at ancient Ao had enormous walls built in this fashion (see siege for more info). Although stone walls were built in China during the Warring States (481–221 BC), mass conversion to stone architecture did not begin in earnest until the Tang Dynasty (618–907  AD). Sections of the Great Wall had been built prior to the Qin Dynasty (221–207 BC) and subsequently connected and fortified during the Qin dynasty, although its present form was mostly an engineering feat and remodeling of the Ming Dynasty (1368–1644 AD). The large walls of Pingyao serve as one example. Likewise, the walls of the Forbidden City in Beijing were established in the early 15th century by the Yongle Emperor.

The Romans fortified their cities with massive, mortar-bound stone walls. Among these are the largely extant Aurelian Walls of Rome and the Theodosian Walls of Constantinople, together with partial remains elsewhere. These are mostly city gates, like the Porta Nigra in Trier or Newport Arch in Lincoln.

Apart from these, the early Middle Ages also saw the creation of some towns built around castles. These cities were only rarely protected by simple stone walls and more usually by a combination of both walls and ditches. From the 12th century AD hundreds of settlements of all sizes were founded all across Europe, which very often obtained the right of fortification soon afterwards.

The founding of urban centers was an important means of territorial expansion and many cities, especially in central and eastern Europe, were founded for this purpose during the period of Eastern settlement. These cities are easy to recognise due to their regular layout and large market spaces. The fortifications of these settlements were continuously improved to reflect the current level of military development.

During the Renaissance era, the Venetians raised great walls around cities threatened by the Ottoman Empire. Examples include the walled cities of Nicosia and Famagusta in Cyprus and the fortifications of Candia and Chania in Crete, which still stand.

The city walls of Jaisalmer, India, also known as Jaisalmer Fort due to its size and complexity in comparison to other city walls. It is a UNESCO World Heritage Site and is considered one of the largest and best preserved city walls, along with its Medieval Indian town, where many of the stone-carved buildings have not changed since the 12th century.
Other Languages
العربية: سور دفاعي
asturianu: Muralla
беларуская: Абарончая сцяна
brezhoneg: Mogeriadur
català: Muralla
čeština: Hradba
dansk: Bymur
Deutsch: Wehrmauer
español: Muralla
Esperanto: Remparo
euskara: Harresi
français: Muraille
galego: Muralla
한국어: 방벽
Ido: Remparo
עברית: חומה
Latina: Moenia
Limburgs: Waermoer
македонски: Бедем
Bahasa Melayu: Tembok pertahanan
Nederlands: Weermuur
日本語: 城壁
norsk nynorsk: Bymur
occitan: Muralha
oʻzbekcha/ўзбекча: Mudofaa devorlari
polski: Mur obronny
português: Muralha
Scots: Fleet-dyke
Simple English: Defensive wall
slovenčina: Hradby
slovenščina: Obzidje
српски / srpski: Бедем
srpskohrvatski / српскохрватски: Bedem
Türkçe: Sur (savunma)
українська: Оборонний мур
اردو: فصیل
Tiếng Việt: Tường thành
中文: 城墙