Despite apocryphal assertions, it is widely accepted among the best-educated wizards of the Wampus Country that there are, in fact, only three Cities of Secrets. These three cities, we are told, hold within them deep, great truths about the nature of reality and the place we call home. Many scholars and historical treatises agree that the Cities of Secrets are numbered three, however different traditions name varied places as those mystical places.
In contemporary sorcerous circles, it is commonly accepted that the three locations consist of the City Behind The Moon, the City Under Everything, and the City Within The Song . Of these, the City Behind The Moon is best-known; a faerie outpost which occasionally exists just outside the atmosphere of our world, it is a place to which we can easily travel if we but know the way, and its denizens occasionally lower themselves to visit the Wampus Country. The second conurbation, about which less is known, is the City Under Everything. A realm of twilight and secrets, this place is, the wizards would have us believe, quite literally under everything - under that lake, under the deepest caves, and under your child's bed; one can only imagine what its denizens best resemble when squinted at in the sickly half-light of its cobblebone streets.
Neither of these storied places, however, are the subject of today's discussion; instead we turn to one of the once-popular candidates for the third mystical node, the City Within The Song. Much of what is supposed regarding this place comes to us from the memoir-tome Strange Futures Wrought By My Own Foolishness, scrawled in mirror-writing by a time-traveling lich under the obvious nom de plume of Endsworth. Mr. Endsworth claims in the book to not only have survived til the end of the universe - thanks in part to his undead condition - but also to have inadvertently caused the whole sordid collapse, as alluded to in the title . Regardless, our concern for the work is singular: the lich Endsworth provides a lengthy diversion regarding the City Within The Song during one of the middle chapters, and it is from this source that we know something of the place.
The City Within The Song, called Ghya-Ma-Hau by its inhabitants, exists simultaneously in several places . The city exists, in some physical sense, on several other demi-planes at once, including those known as "Narcosa" and "Thrice-Cursed Ffu" . Endsworth suggests to us that the City does not exist in the same form in each realm, instead one city dreams the next in a cascade: the Ghya-Ma-Hau we can reach from Wampus Country may be a projection of the dream-selves of the residents of Ghya-Ma-Hau in Narcosa, who themselves are the sweaty nightmares of their own analogs in Ffu. If the lich is to be believed, the citizens of Ghya-Ma-Hau are, generally speaking, aware that they are someone else's dream, and act accordingly - which is to say, with considerable abandon and disregard for their own safety, should the whim strike.
Reaching the City Within The Song from the Wampus Country is not easy to do purposefully, but quite simple to accomplish accidentally. All wizards of our time are familiar with the bazoul, that psychemotive energy field which binds the living creatures of the Wampus Country and even permeates the land itself, like cheap rum poured over a sponge cake. The bazoul is the weave of lives and minds, the unspoken communication between the myriad singularities that populate our world. Every form of communication requires a medium, a language; thus, if the bazoul is the air, there is a song which floats through it, resonating with each mind it passes like a voice against an eardrum. But this is first-year sorcery, and I do not mean to bore you . Suffice it to say that if the bazoul has a song, and that song has a rhythm, then translating said rhythm into physicality would yield Ghya-Ma-Hau: the City Within The Song, and the right altered state of consciousness will provide physical access . Dreamers sometimes go to Ghya-Ma-Hau, and drug addicts, and those in the depths of depression, and those at the pinnacle of joy; when you find yourself so full of sensation or emotion that this world can no longer parse your existence, your mind and body are shunted to the City Within the Song as a safety measure.
The City itself is a massive iridescent - in some manifestations it stands on the surface of the earth, in others it floats in the sky. This immense sphere is populated both on the outer surface, and on the inner, and passing between the two is a simple act of will accompanied by a physical push, as passing gently through a soap bubble. And perhaps a soap bubble is the most appropriate description, as rainbow fractals dance over every surface, seemingly alive, and the entire city is possessed of this unspoken feeling of an impending 'pop' - perhaps yielded by the ephemeral nature of the dreams which form the atoms of Ghya-Ma-Hau. The population of the City may vary by manifestation and time, but it is certainly immense, with the city's footprint covering many square miles of visible land and goodness-knows how many more microplanar spider-holes and transfolded buildings . Things in the distance are transparent in their nonexistence; as you approach, they coalesce out of nothing in a swirl of melted crayon to become real, so long as they are being observed. Once you pass, the shops and sculptures and people may be forgotten and unwatched, and thus dissapate and seep away into invisible drains in the walls of reality. Within the City, thousands go about their dream-business, much of which might be inexplicable to passersby, seeming the actions of mimes and madmen. The streets and walls and buildings shift and morph in reaction to the unspoken needs and fears of the citizenry, making Ghya-Ma-Hau both a playground and a nightmare. Few would travel there intentionally, for there is no safety in wandering the collective unconscious - not only are most humans wracked with constant fears and inadequacies, but many of them are quite stupid, to boot, and all these traits manifest in the City Within the Song.
How many dreamers and mushroom-fiends lose themselves amongst the labyrinthine alleyways of Ghya-Ma-Hau? We cannot know. Nor can we posit whether their visit to the City Within the Song is temporary, or in some way permanent; the place is so permeated with dream-stuff that possibly tonight you will dream your way there, only to then replace your earthly self with a dream of you, slightly altered. The next time your companions note you are not acting like yourself, consider the possibility that you are not, in fact, yourself - you are but a dream-painting of the real you, who is now passed out in an alley in Ghya-Ma-Hau, the City Within the Song.
 The poetic among you will notice the "Behind", "Under", "Within" pattern; I do not recommend placing too much symbolic stock in these words, as the wizards of both today and the Long Long Ago had an inordinate fondness for prepositions.
 If the signposts of apocalypse described by Mr. Endsworth in Chapters Two through Four of his work are interpreted somewhat liberally, then the not-yet-undead Mr. Endsworth is likely alive today, as a young sorcerer.
 "Ghya-Ma-Hau" comes to us from the tongue of the aboriginals of the city, a race of portly toddlers lacking both hair and visible gender. This native race was long ago subjugated, then enslaved, then fashionably modified to be housepets by vivimancers, then rearranged into semisentient furnishings and accessories. Few natives still survive; during his stay in the City, Endsworth rented a native who had been shaped into a small box, in whom he placed his snuff to protect it from Ghya-Ma-Hau's legendary rains.
 I use here the designations given by the Psychlopedia Teratica, as they are in common use by planar scholars even if I personally prefer the hexadecimal system introduced by the learned Ul-Phremion of the Several Matrices, in which the demi-planes are 7A91 and 76CC, respectively.
 If your own university did not cover isoplanar parapsionic metaphysics until third year, you have no one to blame but your parents, who sent you to a sub-par school.
 To review: an encrypted pattern hidden within a psychic song-field, which is also an actual city when you look at it sideways. Wizards who cannot wrap their thinkmeat around such concepts best return to brewing "love potions" for rubes.
 Endsworth himself does not describe the size of the City beyond conveying its enormity, but in one dialogue, he quotes a drinking-companion (one Zebulon the Cruel) as noting Ghya-Ma-Hau to be "at least as big as either the City of Oaks or Chicago, and twice as dangerous as the two combined". Sadly we lack context for this boast.