Taddeo Gaddi built me. I am old,
  Five centuries old. I plant my foot of stone
  Upon the Arno, as Saint Michael’s own
Was planted on the dragon. Fold by fold
Beneath me as it struggles, I behold
  Its glistening scales. Twice hath it overthrown
  My kindred and companions. Me alone
It moveth not, but is by me controlled.
I can...