Around the world and throughout history, numerous peoples have built large fortified walls to protect themselves from their enemies. Whether built out of stone, like the medieval French bastion of Carcassonne or out of red mud like in Morocco’s Taroudant, these walls were designed to ward off invaders. Today, many of these impressive cities have endured the test of time. “If walls survive, it’s because they’re well built and well maintained,” of the UK television series Castle, told Weather.com. “Cities in the Middle Ages and early modern period did spend a lot of money, sometimes up to half their annual budget, maintaining their walls.”

Maintaining the walls can be constantly demanding. In Yemen, preservation involves constantly applying fresh layers of mud, while in France it required the hiring of an architect to conduct an expensive renovation. For cities, like Dubrovnik, preservation involved rebuilding after numerous sieges and two earthquakes.

Here are 15 surviving fortified cities across the globe.

1. San Gimignano, Italy

is a medieval walled city perched on a hill that famous for 15 tall towers that loom over the town and make the city .The town was originally an Etruscan village that grew in prominence and wealth in the 12th century, before . Today, it is an extremely popular tourist destination in Tuscany.

2. Itchan Kala, Uzbekistan

Located on the Amu Darya River in Uzbekistan, is the inner town in the Khiva oasis, once the last resting place for caravans before crossing the desert into Persia, and . Itchan Kala has a history that city that spans over 2000 years, and its walls - built of clay and brick - are 33-feet-high in places. Most of the surviving only date back to the seventeenth century. Still, according to the Organization of World Heritage Cities, it represents one of the best-preserved examples of and it is well known for its , mausoleums, madrasas and palaces.

3. Carcassonne, France

Set high on a hill in the , the ancient walled city of is the largest former fortress in Europe. It renowned for its stout fortified walls, spiky turrets, drawbridges and cobbled streets, which also served as one of the film locations of the 1991 “” movie. The hill on which Carcassone stands has been a fortified settlement for centuries. It , reports Atlas Obscura. Later, it was transformed into a Roman town in the first century BCE. The Visigoths ruled it in the fifth century, and it invaded first by Arabs then Charlemagne in the eighth century. However, according to the website Crème-de-Languedoc, it wasn't until the The city's outer wall and inner rampart were constructed in the 13th century, reports Atlas Obscura. Due to its geographical location, it played an important role . Today, the walled city is listed as a UNESCO World Heritage Site. It is in such good condition, according to the organization, because the famous architect Viollet-le-Duc .

4. Xi’an, China

With a history spanning more than 3,100 years, Xi’an was once called Chang’an (meaning ). It is one of the four ancient capitals of China, ruled for over a thousand years . It was also an , but it is perhaps best known for being the site of the 8,000 buried terra-cotta warriors. Xi’an’s city wall is the most surviving in China, spanning eight-and-a-half miles. The wall has been restored three times throughout its history: first in 1568 (when its dirt and lime wall was rebuilt with bricks), then in 1781 and recently in 1983.

5. Veliky Novgorod, Russia

Located in near the Volkhov river and Lake Ilmen in North-West Russia, Velikiy Novgorod was founded in the 9th century and was the first capital of Russia. It was one of the most important artistic and political centers in the country for about 600 years, and at its peak, the medieval city had one of Europe’s largest populations. The red brick walls fortifying of the still standing today were built in the 15th century and enclose St. Sophia’s Cathedral and the Gothic Archbishop’s Palace.

6. Shibam, Yemen

Surrounded by a fortified clay wall, Shibam is a city located on the southern tip of the Arabian Peninsula in Yemen. Known as the “,” the city is comprised of 500 “ ranging from five to eleven stories high, reports Atlas Obscura. The walled city is built on a hillock, allowing it to escape floods. , but there are some older houses and monuments remaining, such as the Friday Mosque dating back to 904. All of the town’s structures demand continual maintenance to keep them from crumbling due to the erosion caused by wind, rain and heat, reports Atlas Obscura. are constantly applied to the walls.

7. Avila, Spain

The walled city of was founded in the 11th century to protect the Spanish territories from the Moors. Located in the Castile-Léon region in northwestern Spain, this is the one of the best-preserved medieval bastions in the country, inspite of its . The walls span over 8,200 feet and feature 88 semi-circular watchtowers, more than .

8. Pingyao, China

Humans have settled since Neolithic times, but the walled city still standing today was founded in the 14th century. The fortified city was laid out according to the , reports The Telegraph, and it remains one of the best-preserved cities in the country. Its walls were built of grey bricks and were . These fortifications span about four miles in circumference and include 72 watchtowers, six gates and a moat outside them.

9. Dubrovnik, Croatia

Situated on the beautiful Dalmatian Coast, Dubrovnik is a walled city founded in the seventh century by refugees from Epidaurum, an ancient Greek colony. Once an independent State and an important seaport in the 13th century, this remains remarkably well preserved despite two earthquakes (in 1667 and 1979) and being in the early 1990s. Today, the coastal town remains a popular tourist destination, and, reports the Huffington Post, it as one of the of the popular TV show “Game of Thrones.”

10. Gradara, Italy

Located along the border of Le Marche and Emilia Romagna in Italy, Gradara is a medieval walled city that is home to one of the best preserved castles in Italy. The city walls were , a family who ruled over the city until 1463. The city is also in the country. Today, the city is a popular destination for tourists.

11. Harar, Ethiopia

The historic walled city of Harar (formerly written as Harrar) lies in the eastern part of Ethiopia, surrounded by deserts and savannah on a plateau with deep gorges. This packs , according to Lonely Planet, and its walls were built between the 13th and the 16th century to protect its inhabitants from harm. Harar is one of Islam’s holiest cities, containing 82 mosques and 102 shrines. It is also the location from which the Muslim leader led many fierce battles during the 16th century, reports the BBC.

12. Tallinn, Estonia

The Old Town of Tallinn is a situated on the northern coast of the country on the Baltic Sea. Although it is believed that the there in the 10th or 11th century, the between the 13th and 16th centuries. Over its history, the city saw many battles and wars, but it was when it fell under Swedish rule between the 16th and 18th century that its defensive walls were established. Today, many of the walls and gates to the old town are still standing, making it an interesting visit.

13. Obidos, Portugal

Located on a hill about 62 miles north of Lisbon, Obidos is an eighth century Moorish fortified town that was conquered by the first king of Portugal, King Alfonso Henriques in 1148. The town was given as a by King Dinis to Queen Isabel in 1282, reports the town’s tourism website. The walled city remained the property of the , according to Fodors. Obidos was also once a strategic seapor, but today, because of the silting of the harbor, the former docks are dry and filled with cottages and cultivated fields.

14. Taroudant, Morocco

Taroudant (also spelled “Taroudannt”) is an authentic Berber town that was once their ancient Souss capital. Located in the middle of a valley, it is located south of the snow-peaked High Atlas Mountains and about 50 miles away from Agadir. This town is sometimes called “,” according to Lonely Planet, and it is surrounded by red-mud walls that were built in the 16th and 17th century under the Saadi Dynasty, reports Complete Morocco. The fortified-walls are about 3.7 miles long.

15. York, England

Located in northern England, on the remains of earlier Roman walls. are the most , according to HistoryOfYork.org.uk, since most other cities, including London, destroyed their medieval walls in the 19th century.

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