[Legate of Amon Lanc]

Originally Posted by Ibrîniðilpathânezel

Minas Morgul, by the bye, was originally a fortress of Gondor, Minas Ithil, and it would make sense that it look like other places built by the Numenoreans. -- Minas Tirith, Orthanc, etc. But I don't believe they built Dol Guldur -- or is my memory just failing me?

Your memory is not failing you, Amon Lanc was originally probably a place with just some elven settlement, and later the fortress (of Dol Guldur at that time already) was built there later.

Originally Posted by Kuruharan

Isn’t a partial description of Dol Guldur given in the Fellowship of the Ring?

I don't think so. There is the moment where Frodo looks from Cerin Amroth and sees only dark cloud. Haldir, or who is that there, says there is "forest of dark fir" around Guldur and that there is "black cloud above it lately", but nothing much more. And then, when Frodo looks from Amon Hen, he sees only battle of Men and wild beasts in Mirkwood, but not Dol Guldur.

Originally Posted by Kuruharan

That is an interesting question about how Gandalf knew. I think Gandalf just recognized Sauron’s presence in the place, having known him before when they were singing the Music. I think he picked up the vibe, as it were.

I thought about similar things as well. But then the question arises - how close would Gandalf need to be to recognize Sauron? In Moria, when he was placing a spell upon the door on whose other side the Balrog was, he merely sensed "something he never sensed before". He also sensed the Balrog when he entered the room, but he did not realise it was the Balrog until he saw him (and Legolas said it). So, I think even though he may have had his expectations to find Sauron there, he had to come quite close to him - and still, I'm sure he'd double-check it and not rely just on some feeling - he had to be absolutely sure, not to say "maybe there's Sauron, or maybe there's a Balrog", for example. He seems pretty convinced when speaking to Elrond about it:

Originally Posted by Silmarillion

True, alas, is our guess. This is not one of the Úlairi, as many have long supposed. It is Sauron himself who has taken shape again and now grows apace; and he is gathering again all the Rings to his hand; and he seeks ever for news of the One, and of the Heirs of Isildur, if they live still on earth.

Sounds like some enspionage old Gandalf did there, and "taken shape" - may even refer to the fact that he saw him?

By the way - to avoid a double-post, Gandalf indeed entered Dol Guldur in disguise:

Originally Posted by UT, the Quest of Erebor

I remembered a dangerous journey of mine, ninety-one years before, when I had entered Dol Guldur in disguise, and had found there an unhappy Dwarf dying in the pits.