Fortress in the context of "West Ukraine"

A citadel is the most fortified area of a town or city. It may be a castle, fortress, or fortified center. The term is a diminutive of city, meaning "little city", because it is a smaller part of the city of which it is the defensive core.

In a fortification with bastions, the citadel is the strongest part of the system, sometimes well inside the outer walls and bastions, but often forming part of the outer wall for the sake of economy. It is positioned to be the last line of defence, should the enemy breach the other components of the fortification system.

A siege (from Latin sedere 'to sit') is a military blockade of a city, or fortress, with the intent of conquering by attrition, or by well-prepared assault. Siege warfare (also called siegecraft or poliorcetics) is a form of constant, low-intensity conflict characterized by one party holding a strong, static, defensive position. The attacking party is said to be laying siege. Consequently, an opportunity for negotiation between combatants is common, as proximity and fluctuating advantage can encourage diplomacy.

A siege occurs when an attacker encounters a city or fortress that cannot be easily taken by a quick assault, and which refuses to surrender. Sieges involve surrounding the target to block provision of supplies and reinforcement or escape of troops (a tactic known as "investment"). This is typically coupled with attempts to reduce the fortifications by means of siege engines, artillery bombardment, or mining (also known as sapping), or the use of deception or treachery to bypass defenses.

The Colosseum (/ˌkɒləˈsiːəm/ KOL-ə-SEE-əm; Italian: Colosseo [kolosˈsɛːo], ultimately from Ancient Greek word "kolossos" meaning a large statue or giant) is an elliptical amphitheatre in the centre of the city of Rome, Italy, just east of the Roman Forum. It is the largest ancient amphitheatre ever built, and is the largest standing amphitheatre in the world. Construction began under the Emperor Vespasian (r. 69–79 AD) in 72 and was completed in AD 80 under his successor and heir, Titus (r. 79–81). Further modifications were made during the reign of Domitian (r. 81–96). The three emperors who were patrons of the work are known as the Flavian dynasty, and the amphitheatre was named the Flavian Amphitheatre (Latin: Amphitheatrum Flavium; Italian: Anfiteatro Flavio [aɱfiteˈaːtro ˈflaːvjo]) by later classicists and archaeologists for its association with their family name (Flavius).

The Colosseum is built of travertine limestone, tuff (volcanic rock), and brick-faced Roman concrete. It could hold an estimated 50,000 to 80,000 spectators at various points in its history, having an average audience of some 65,000; it was used for gladiatorial contests and public spectacles including animal hunts, executions, re-enactments of famous battles, dramas based on Roman mythology, and briefly mock sea battles. The building ceased to be used for entertainment in the early medieval era. It was later reused for such purposes as housing, workshops, quarters for a religious order, a fortress, a quarry, and a Christian shrine.

Yeni-Kale (Ukrainian: Єні-Кале; Russian: Еникале; Turkish: Yenikale; Crimean Tatar: Yeñi Qale, also spelled as Yenikale and Eni-Kale and Yeni-Kaleh or Yéni-Kaleb) is a fortress located on the shore of Kerch Strait in the city of Kerch.

A defense line or fortification line is a geographically recognizable line of troops and armament, fortified and set up to protect a high-value location or defend territory, which is an "area of defense".

A defense line may be based on natural difficult terrain features, such as rivers or marshes, mountain ranges, or coastlines; temporary field fortification works such as trenches; and/or more permanent fortifications such as fortresses and bunkers.

Guanzhong (Chinese: 关中, formerly romanised as Kwanchung) region, also known as the Guanzhong Basin, Wei River Basin, or uncommonly as the Shaanzhong region, is a historical region of China corresponding to the crescentic graben basin within present-day central Shaanxi, bounded between the Qinling Mountains in the south (known as Guanzhong's "South Mountains"), and the Huanglong Mountain, Meridian Ridge and Long Mountain ranges in the north (collectively known as its "North Mountains"). The central flatland area of the basin, known as the Guanzhong Plain (关中平原; pinyin: Guānzhōng Píngyuán), is made up of alluvial plains along the lower Wei River and its numerous tributaries and thus also called the Wei River Plain. The region is part of the Jin-Shaan Basin Belt, a prominent section of the Shanxi Rift System, and is separated from its geological sibling — the Yuncheng Basin to its northeast — by the Yellow River section southwest of the Lüliang Mountains and north of the river's bend at the tri-provincial junction among Shaanxi, Shanxi and Henan.

The name Guanzhong means "within the passes", referring to the four major mountain pass fortresses historically defending the region. The region was the traditional heartland of Qin state during Zhou dynasty and thus often nicknamed the "800 li of Qin land". The Yellow River, Lüliang Mountains and the eastern end of the Qinling separate the region from the (then) politically orthodox Central Plain, which is located east of the strategic Hangu Pass and therefore was historically referred as the Guandong ("east of the pass") region by the Qin people, who later conquered the eastern states and unified China as a centralized empire — the Qin dynasty — for the first time during the 3rd century BC. Afterwards, subsequent prominent dynasties such as the Han and Tang (both considered China's historical golden ages) also had the crownland established in the Guanzhong region.

Western Ukraine or West Ukraine (Ukrainian: Західна Україна, romanized: Zakhidna Ukraina, IPA: [ˈzɑxidnɐ ʊkrɐˈjinɐ]) refers to the western territories of Ukraine. There is no universally accepted definition of the territory's boundaries, but the contemporary Ukrainian administrative regions (oblasts) of Chernivtsi, Ivano-Frankivsk, Lviv, Ternopil and Zakarpattia (which were part of the former Austro-Hungarian Empire) are typically included. In addition, Volyn and Rivne oblasts (parts of the territory annexed from the Polish–Lithuanian Commonwealth during its Third Partition) are also usually included. In modern sources, Khmelnytskyi Oblast is often included because of its geographical, linguistic and cultural association with Western Ukraine, although this cannot be confirmed from a historical and political point of view. It includes several historical regions such as Carpathian Ruthenia, Halychyna including Pokuttia (the eastern portion of Eastern Galicia), most of Volhynia, northern Bukovina and the Hertsa region, and Podolia. Western Ukraine is sometimes considered to include areas of eastern Volhynia, Podolia, and the small northern portion of Bessarabia.

The area of Western Ukraine was ruled by various polities, including the Kingdom of Galicia–Volhynia, which became part of the Polish–Lithuanian Commonwealth, but also the Principality of Moldavia; it would then variously come under rule of the Austrian Empire, Austria-Hungary, the Second Polish Republic, the Kingdom of Romania, and finally the Soviet Union (via the Ukrainian Soviet Socialist Republic) in 1939 and 1940 following the invasion of Poland and the Soviet occupation of Bessarabia and Northern Bukovina, with the borders finalized after the end of World War II. After the dissolution of the Soviet Union, it became part of the independent Ukrainian state.