Caernarfon Castle built
1283 CE.
Shown on the map at 53.139°, -4.277°.
Caernarfon Castle (Welsh: Castell Caernarfon; Welsh pronunciation: [kastɛɬ kaɨrˈnarvɔn]) is a medieval fortress in Gwynedd, north-west Wales. The first fortification on the site was a motte-and-bailey castle built in the late 11th century, which King Edward I of England began to replace with the current stone structure in 1283. The castle and town established by Edward acted as the administrative centre of north Wales, and as a result the defences were built on a grand scale. There was a deliberate link with Caernarfon's Roman past—nearby is the Roman fort of Segontium—and the castle's walls are reminiscent of the Walls of Constantinople. While the castle was under construction, town walls were built around Caernarfon. The work cost between £20,000 and £25,000 from the start until the work ended in 1330. Although the castle appears mostly complete from the outside, the interior buildings no longer survive and many parts of the structure were never finished. In 1294 the town and castle were sacked and captured by Madog ap Llywelyn during his rebellion against the English, but were recaptured the following year.
Text from the Wikipedia article Caernarfon Castle, licensed CC BY-SA 4.0.