"Lord, there is no such city anywhere, But all a vision."

And Gareth likewise on them fixt his eyes
So long, that even to him they seemed to move.
Out of the city a blast of music pealed.
Back from the gate started the three, to whom
From out thereunder came an ancient man,
Long-bearded, saying, 'Who be ye, my sons?'

Then Gareth, 'We be tillers of the soil,
Who leaving share in furrow come to see
The glories of our King: but these, my men,
(Your city moved so weirdly in the mist)
Doubt if the King be King at all, or come
From Fairyland; and whether this be built
By magic, and by fairy Kings and Queens;
Or whether there be any city at all,
Or all a vision: and this music now
Hath scared them both, but tell thou these the truth.'

Then that old Seer made answer playing on him
And saying, 'Son, I have seen the good ship sail
Keel upward, and mast downward, in the heavens,
And solid turrets topsy-turvy in air:
And here is truth; but an it please thee not,
Take thou the truth as thou hast told it me.
For truly as thou sayest, a Fairy King
And Fairy Queens have built the city, son;
They came from out a sacred mountain-cleft
Toward the sunrise, each with harp in hand,
And built it to the music of their harps.
And, as thou sayest, it is enchanted, son,
For there is nothing in it as it seems
Saving the King; though some there be that hold
The King a shadow, and the city real:
Yet take thou heed of him, for, so thou pass
Beneath this archway, then wilt thou become
A thrall to his enchantments, for the King
Will bind thee by such vows, as is a shame
A man should not be bound by, yet the which
No man can keep; but, so thou dread to swear,
Pass not beneath this gateway, but abide
Without, among the cattle of the field.
For an ye heard a music, like enow
They are building still, seeing the city is built

To music, therefore never built at all,
And therefore built for ever.'

 ～ Idylls of the King (1872) by Alfred, Lord Tennyson