Yes You have come upon the fabled lands where myths Go when they die, But some, especially the Brummagem capitalist Juju, have arrived prematurely. - James Fenton

Poetry is not a metrical exercise.

Tennyson follows his feelings in creating each line. He follows the music in his head. If you had asked him, at the end of the day, to describe the prosody of the poem to you, he would no doubt have had to think for a moment before he could answer you, not because he was ignorant of the terms, but because he had been writing a poem, not a metrical exercise. At every point, he was exerting his free will. And the outcome of that exertion was the form.

It is not what they built. It is what they knocked down.
It is not the houses. It is the spaces between the houses.
It is not the streets that exist. It is the streets that no longer exist.