Castles and Fortifications in Middle-earth

[Legate of Amon Lanc]

Originally Posted by Rumil

One thing about the 3rd Age fortifications is thar they had been built by the Numenoreans using some mysterious technology or technique.

Orthanc is desrcibed as being of dark stone and very smooth, such that the ents could not gain a hand/tendril hold. To me this suggests some sort of stone like marble, that could be highly polished and almost glassy-smooth. I guess the joints between the blocks must have been very thin and accurate, this could be a product of great craftsmanship, such as ancient South American stone construction that is amazingly precisely put together without recourse to cement and mortar.

Well, it's said that Orthanc seemed like made of one piece of stone (or perhaps carven out of one piece of stone?), and I actually think it as well may have been just of one piece of stone. So really, no blocks, no joints, just one piece of stone. But I guess that would leave it out of the line of usual fortress-building.