As fast as an eagle, as slow as a slug. As tall as a tree, as small as a bug. Sometimes in front, sometimes behind. Never on top, and always aligned. What is it?

"The beginning of eternity
The end of time and space
The beginning of every end,
And the end of every place."

I lived in a city that held as much as it could,
So I moved to another that repaid what it should.
The third had very little, with not much to be found,
The fourth was very boring, with no change in the sound.
The fifth was a jungle; wild beasts roamed the in street,
The sixth was so foggy you could not see past your feet.
The seventh was on the move; I could barely keep the pace,
The eighth was so evil; a whole city in disgrace.
The ninth was off-center; the people were bizarre,
The tenth was quite truthful; where honesty is par.
The eleventh was so wise; the acumen hurt my brain,
So I settled in a twelfth, because it was so plain.