defensive wall

Defensive walls were used to enclose settlements from prehistory into the modern 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. Many town walls were supplemented with towers and were frequently surrounded by dry ditches or wet moats. The most important and expensive components of town walls were the gates. The practice of building these massive walls, though having its origins in perhistory, was refined during the rise of city-states, and energetic wall-building continued into the medieval period and beyond in certain parts of Europe. Often the walls proved impenetrable to attacking armies which then laid siege to the city. Nonetheless, walls also had a number of important non-military functions. They symbolised the wealth and prestige of communities, served as barriers against disease and 'low level' types of threat and were valued by citizens as perambulations, while gates acted as toll-collection points and were often showpieces of municipal pride. Within walled cities, the poor and "noxious trades" were generally located near or outside the walls.

Canada

Quebec City, Quebec is the only fortified city north of Mexico whose walls still exist.

China

Great Wall of China
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.
Jingzhou
Walled villages can still be found in Mainland China and Hong Kong.

Croatia

Dubrovnik has well-preserved city fortifications including towers, gate, rampart walk and two citadels guarding the docks.
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.

France

Germany

The German Democratic Republic claimed that the Berlin Wall (and the whole DDR border system) was defensive; but it was rather intended to prevent unauthorized emigration.

Israel

Jerusalem's Old City Walls
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.

Ireland

Pale

Middle East

Jericho's Ancient City Walls - probably the most ancient stone wall ever discovered.

Morocco and Western Sahara

In the 1980s, Morocco built a system of sand wall defenses, the Moroccan Wall or Western Sahara walls, to keep the Polisario out of the Western Sahara.

Philippines

Intramuros - partially preserved, partially restored after WWII. Original walls are still on are well preserved.
Fort San Pedro - in Cebu
Fort San Antonio Abad - in Manila
Fort Pillar- a Spanish defence fort in the island of Mindanao

Poland

Warsaw - partially preserved, partially restored after WWII
Cracow - only the barbican and some traces preserved
Zamosc - complete renaissance and 19th century walls preserved
Torun
Grudziadz
Wloclawek
Tyniec

Spain

vila
Barcelona has portions of a Roman wall.
Girona
Lugo has a complete ringwall, some parts dating back to Roman times.
Toledo

Turkey

Istanbul

United Kingdom

Fragments of London Wall, the wall that once surrounded the Roman town of Londinium, are still visible just outside the Museum of London and at Tower Hill.
The remnants of the city walls of York are both a shortcut above the streets and, as in many places, a tourist attraction.
The walls of Coventry were demolished in 1662 and now only a few fragments survive.
Berwick-upon-Tweed
Chester
Chichester
Conwy
Derry
Stirling
Warwick

United States

Wall Street, in New York City, is named after New York's old city wall, long since dismantled.

exeter, wisconsin
jefferson, green county, wisconsin
jordan, wisconsin
monticello, green county, wisconsin
mount pleasant, green county, wisconsin
spring grove, wisconsin
sylvester, wisconsin
washington, green county, wisconsin
york, green county, wisconsin
brooklyn, green lake county, wisconsin
mackford, wisconsin

manchester, green lake county, wisconsin
markesan, wisconsin
seneca, green lake county, wisconsin
st. marie, wisconsin
avoca, wisconsin
barneveld, wisconsin
brigham, wisconsin
clyde, wisconsin
cobb, wisconsin
eden, iowa county, wisconsin
hollandale, wisconsin

Defensive Wall