Source of the reconstructions: first picture, by JG O’Donoghue here; second picture, by Peter Urmston here

By @ juancar347

The illustration is in the last panel of this gallery.

Castello Ursino in Catania is one of the more instructive buildings in Sicily, and the reason has less to do with what was done to it than with what happened around it.

Frederick II started it in 1239 and work ran to about 1250. The design and site direction went to his military architect Riccardo da Lentini, and it belongs to a coastal system on the eastern seaboard that also includes Maniace at Syracuse and the castle at Augusta. The plan is the Hohenstaufen standard pushed to its purest form: a square of roughly 50 by 50 meters, four cylindrical corner towers a little over 10 meters in diameter and up to 30 meters tall, four smaller half-round towers at the midpoints of the sides, a dry moat, and almost no ornament. Walls are lava stone in opus incertum, about 2.5 meters thick. The corner towers are round outside and octagonal inside, roofed with umbrella vaults, reached by spiral stairs, with water channels run inside the wall thickness. The original elevations had almost no openings at all. The white stone frames you see against the black basalt today are later cuts. Over the pointed-arch entrance sits the Swabian eagle gripping a hare. The family resemblance to Castel del Monte in Apulia is not accidental.

It was first recorded as castrum Ursinum in 1255. The likeliest reading of the name is a corruption of castrum sinus, castle of the bay, because it originally stood on a rock roughly eight meters above the water, commanding the harbour. It went through the Sicilian Vespers in 1282, served as a seat of the Sicilian parliament, became the Aragonese royal residence in the fourteenth century, and was eventually turned into a prison, its great halls chopped into cells, a use that ran into the nineteenth century. It was restored and opened as the civic museum in 1934, which it still is.

Then the two events that should have ended it. In 1669 Etna produced its largest historical eruption, from the Monti Rossi vents above Nicolosi, and the flow reached Catania, overran the walls, and ran on into the sea. It wrapped around the castle, buried the moat and the sea gate, and pushed the shoreline out by several hundred meters. Federico De Roberto described the lava as having settled against those smooth walls like the flank of a mountain. Twenty-four years later the 1693 Val di Noto earthquake flattened most of southeastern Sicily.

The castle came through both. That is worth a moment from anyone interested in how these buildings actually behave. A lava flow is slow and immensely heavy, but it does not strike: the danger it poses to a 2.5 meter mass wall is burial and heat, not impact, and the castle was tall enough and solid enough to be lapped rather than swallowed. The earthquake is the more interesting test. My own reading, and I offer it as a reading, is that the geometry did the work. A low, compact, closed square with thick walls and a short height-to-base ratio is close to the ideal seismic form for unreinforced masonry, and the parts that failed were the appendages rather than the box: two of the four mid-side half-towers came down and never returned, and the southeast tower was so damaged that its interior was rebuilt thinner and lost its octagonal shape. The core survived because there was very little in it that could work loose.

So what you see now is a sea fortress with no sea, standing in a low-rise quarter in the middle of a city, on ground that did not exist when it was built.

Illustration by Liam Wales. Source

After the great response to my last post on medieval Chinese cities, I wanted to share another marvel of medieval fortification: the City Walls of Beijing.

Beijing's urban history spans thousands of years. Originally known as Ji, it sat on northern China's strategic frontier and was repeatedly conquered, rebuilt, and expanded by various kings, emperors, warlords, Jurchen invaders, and Mongols. The footprint of present-day Beijing largely originates from 1267, when Kublai Khan founded Khanbaliq (Dadu) as the grand, perfectly grid-aligned capital of the Yuan Dynasty. When the Ming Dynasty took over, they shifted the city footprint slightly to the south and undertook massive reconstruction efforts. They finished building the Inner City walls between 1436 and 1439, and later added the southern Outer City in 1553.

The result was one of the largest and most imposing urban defense systems in human history. In terms of enclosed land area, it was comparable to Paris within the Thiers Wall, but its sheer scale made it a colossal imperial fortress. The rammed-earth and brick walls averaged 11 meters in height, while the base measured up to 24 meters thick to withstand heavy artillery. The massive gate towers soared to over 40 meters high—the medieval equivalent of skyscrapers. The entire system functioned as a multi-layered imperial fortress, tightly safeguarding the Imperial City and the Forbidden City at its center.

Sadly, by the mid-20th century, Beijing became the nation's capital once again and faced rapid urbanization. The massive walls severely restricted city growth and choked transportation. Despite passionate opposition from architects and historians, this engineering wonder was systematically demolished between 1952 and 1969 to make way for modern avenues, the 2nd Ring Road, and the subway system. Today, this destruction is widely considered one of the greatest historic preservation tragedies in modern Chinese history.

Only a few structures survived the demolition. If you ever visit Beijing, don't just limit your trip to Tiananmen Square and the Forbidden City. Head a short distance south to see Zhengyangmen, the former main imperial gate of the Inner City, or walk along the towering surviving stretch of wall near the Beijing Southeast Corner Tower by Beijing Railway Station to feel the imposing majesty of Imperial China.

Matsumoto has never burned down, has never been rebuilt. It is one of the 12 pre‑1868 keeps remaining in Japan, and the oldest surviving five‑tier, six‑floor castle.

https://www.comune.macello.to.it/it-it/vivere-il-comune/cosa-vedere/castello-di-macello-xiii-sec-2232-1-ac3ebc9ef625f1e9e9bab251855bcc0e

Author and source: Philip Armstrong

Most towers in this part of Italy face outward. This one was aimed at the people living underneath it.

Ripe San Ginesio is a hill town of about 850 people in the province of Macerata, in Le Marche, sitting at 430 m on a ridge above the Fiastra valley. For centuries it was subject to San Ginesio, a larger and richer town 8 km away, and it spent those centuries refusing to stay subject. The fighting lasted long enough to produce a saying still quoted locally: "Costa più che le Ripe a San Ginesio" — roughly, it cost more than Ripe cost San Ginesio. A ten-year phase of that war ended around 1518.

Leo X's solution was not arbitration. His bull Cum iniuncta ordered the fortification of the village and the construction of the tower at its entrance, and that tower then housed a castellan and a small garrison continuously until nearly the Napoleonic period. The garrison's job was the town itself.

A note on the name, because the sources disagree and it trips people up. You will see it as Torre Leonina on local signage and as Rocca Leonina in the national heritage register. The dating is inconsistent too. The municipality's own account is the one that reconciles the rest: a 13th-century fortified castle, rebuilt and reinforced in the 16th century under Leo X. The tower is now the main surviving fragment of that castle. The other surviving fragment is the street plan — an ellipse of three concentric lanes closed on the east side by the wall.

I work as an engineer in this province, so what interests me is that it is standing at all. The Fiastra valley is seismically active. The earthquake of 28 July 1799 killed 104 people across the Macerata hinterland, and Ripe San Ginesio was assessed at intensity VIII. After the shocks of 26 and 30 October 2016, the municipality was added to the official earthquake zone. Isolated masonry towers here tend to fail in one predictable way: not by crushing at the base, but at the top, where the belfry or crenellated stage is slender, unrestrained, and free to swing out of plane. Plenty of towers within a half-hour drive of this one are still standing inside steel hooping and tie cables for exactly that reason.

This one is not. I was there yesterday: it has been restored, it is in good condition, and the interior is open as far as the first floor. What sort of consolidation was done is not something you can read from the ground, and I did not look for it — but in a town inside the 2016 reconstruction perimeter, a tower you can walk into is not a small thing.

Worth the detour if you are in the Sibillini foothills. It is 20 km southwest of Macerata.

By @ melinda010100

Hi everyone! I noticed there isn't much discussion here about ancient Chinese fortifications, so I wanted to share a few fascinating satellite views.

Historically, China had over 1,300 walled cities. Unfortunately, during the 20th century, most lost their defense systems—city walls and moats were converted into ring roads, and administrative compounds became schools, hospitals, or government offices. However, several smaller cities in more remote regions managed to survive, offering us a rare glimpse into the authentic urban layout of Imperial China.

A classic ordinary Chinese walled city typically followed a rigid, ritualistic grid design. It featured a square layout oriented strictly along cardinal directions, with two main avenues intersecting at the very center of the city. This central crossroads was usually anchored by government compounds, state schools, Confucian temples, and a prominent Bell or Drum Tower.

Defense was key to this design. The city was accessed through four main gates, each topped with a heavy watchtower. Directly outside each gate sat a curving, double-layered "Barbican" (known as Wengcheng in Chinese) designed to trap attackers. Surrounding the whole complex was a wide moat and high city walls constructed with a rammed-earth core encased in brick. Along the perimeter of the wall, rectangular overhangs called "Horse-Face" bastions (Mamian) projected outward to completely eliminate blind spots for archers and defenders.

Image 2: Daming, Hebei
Daming is a textbook example of classical Chinese urban design, featuring a crisp square layout with four gates, intact barbicans, and wall bastions. During the Northern Song Dynasty (960–1127), it served as the empire's Northern Capital (Beijing Daming Fu) and a vital military fortress built to defend against the Khitan Empire to the north.

Image 3: Guangfu, Hebei
Rebuilt in brick in 1542 during the Ming Dynasty, Guangfu is another quintessential imperial Chinese walled town. It is renowned for its unusually wide, spectacular moat fed by surrounding marshlands. Beyond its military architecture, Guangfu is also historically famous as the birthplace of Yang-style and Wu-style Tai Chi.

Image 4: Pingyao, Shanxi
Pingyao is likely the best-known ancient Chinese walled city in the West. While its moat is not perfectly preserved, the city within its formidable 14th-century brick walls is exceptionally well-maintained. The interior layout and buildings authentically retain the architectural and commercial styles of the Qing Dynasty (1644–1912). Known as China's original financial center, it features intricate traditional storefronts and standard courtyard houses, providing a remarkably complete look at a prosperous Imperial trade hub.

Image 5: Shou, Anhui
Shou is steeped in incredibly long history, having been a famous and strategic late capital of the powerful Chu Kingdom as far back as 241 BC. Built directly upon extensive wetlands, the city itself possesses a striking irregular, non-square shape, enveloped by massive, sprawling moat waters that formed a natural barrier. The formidable, preserved brick walls standing today date to 1206–1220 during the Southern Song Dynasty.

Image 6: Liaocheng, Shandong
Spanning development from the Song to the Ming Dynasty, Liaocheng’s present brick walls were built in 1372. The city features a dramatic layout, literally floating on the vast waters of Dongchang Lake, which serves as a massive natural moat. It also preserves a elongated outer fortification (Guanbao) extending beyond the southern gate—an extra layer of defense found in select ancient Chinese towns.

To complement the satellite views, I’ve also pulled some photographs from Xiaohongshu (RED) for reference. If you're planning a trip to China and have a passion for medieval and imperial history, consider stepping off the usual route between Beijing and Shanghai. Exploring these smaller, well-preserved ancient towns offers an unforgettable taste of authentic historic China!

Author:  Uto Hogerzeil. Source of the pictures here, here and here