The castle at Mont Orgueil is well worth a visit if you are on Jersey (wiki link). It is remarkably intact having been in use from an iron age fort through to the German occupation.
Its position overlooking Gorey and the Royal Bay of Grouville.
The introduction has a nice model of the castle, but it's difficult to photograph with the reflection
Looking up at the mssively reinforced keep with a Tudor artillery position on the right.
Sir Hugh Calveley (a cheshire lad) heavily involved in the HYW (link)
The view to the north.
The reason for the reinforced keep was to be able to have guns on top to contest the hill that overlooks the rest of the castle.
German conversion of the turrets into observation posts.
View from Gorey pier below
Of course Mont Orgueil was outdated in the age of gunpowder and was replaced as the principle fortification by Fort Elizabeth (next post) but it remained in use, especially by the Napoleonic spymaster Phiippe d'Auvergne.