Grand Fortresses are beaten by Great Walls in nearly every respect. The unique features need to be improved upon or swapped with the Great Walls.The Fortress claims to 'considerably improve the military capabilities of its owner.' This is demonstrability false, especially in comparison to the Great Walls. Lets compare the unique features.Fortress unique features:Walls unique features:As you can see great walls have access to more features that provide troops and siege defence. Based on troop count alone walls can provide up to 550*7 troops. As each feature provides troops to every holding within the province. Fortresses can only provide 100. Walls also provide a ton of siege defence at the same time.It's really a no brainer as to which one to pick, the only thing the fortress has going for it is the unique artifact.