Defensive walls were common from the ancient period into the medieval period. Generally, these are referred to as city walls or town walls, although there were also walls, such as the Great Wall of China and the Atlantic Wall, which extended far beyond the borders of a city and were used to enclose vast regions.
City walls were still occasionally used as late as the 19th century, although by this time they were generally of wood (rather than stone) construction and used only around small frontier settlements. City walls also had towers and were frequently surrounded by trenches.
The practice of building these massive walls had been developed sometime before the rise of the Sumerian Empire and was connected with the rise of city-states.
Often the walls proved impenetrable to attacking armies which then laid siege to the city.
Within walled cities, the poor and "noxious trades" were generally located near or outside the walls.
Chinese cities occasionally have remnants of city walls that were built in the Ming Dynasty and designed to withstand artillery bombardment. Chinese cities generally outgrew their walls, which fell into disrepair in the Qing dynasty. The city of Xi'an has well-preserved walls with a water filled moat that is a tourist attraction incorporating small parks surrounding a busy and modern area of the city.
The walls of Beijing were demolished during the 1960s to open large streets around the city. A metro line also follows the location of the former city walls.
Stone walls built in 14th-16th century, at the isthmus of the Pelješac peninsula, to the north of Dubrovnik; 890 meters long town wall and 5 km Great Wall outside the town
Karlovac city walls, built in 1579 as a six-point star with bastions.
The walls of Akko (Acre) - 18th century modern Ottoman fortification able to withstand cannons attack. The wall has been restored and now includes rampart for tourists.
The Great Wall, symbolizing the famous, grand and splendid ancient is just like a giant dragon starting from Yalu River and crossing high mountains, deserts and grassland to world from east to west in the northern part of China.
They built a high wall, which was called "Square Wall" surrounding their own territories that could make the invading enemy feel terrified by the high wall, so it was also known as the Qi Great Wall and!the Chu Great Wall.
Especially the high walls in the northern part of China built by Qin, Zhao and Yan were linked up and extended into a Great Wall to ward off harassment by the Huns (an ancient nationality in northern China) and for the use of further defensive project.