I`ve always been a bit underwhelemed by forts in Civ - a 25% defense bonus is not that great, especially if you have to cut down a forest on a hill tile. This gives a negative defense bonus (75% -> 50%). I was thinking of the virtually impregnable fortresses during the Crusades (eg Krak des Chevaliers), and thought that it`d be great to be able to build a strong fortress in hostile lands, instead of having to found a city and build a castle within it. Would also be good if you could build a castle on mountain tiles, but don`t think this would be possible. The castle could be named, just like a city, work one ring of tiles, and have a fortification bonus of, say, 50% plus 4 times whatever terrain it was built on (150% on a hill). But the number of units you could base there would depend on the size of the fortress (it would grow in the same way as a city). It just seems crazy that forest/hill gives more of a defensive bonus than fort/hill.
They would have to cost a lot of gold and worker turns, and maybe the Civ would also have to have access to a quarry.
They would have to cost a lot of gold and worker turns, and maybe the Civ would also have to have access to a quarry.