Orinder, Flying Mecha-Fortress of Galadriel

This was quite an unexpected place to spend my dreams last night.  It's probably as well that it phased into my brainspace rather than Tolkien's, as Lord of the Rings might otherwise have been a far shorter and strangely unsatisfying book.

It could fold down into a dimensionally transcendental winkle-shell, too.

It seemed me that there was at least a novel's worth of Ripping Yarn going on within the city, but - alas - I can no longer remember one point of it.