'Ironic rainbow'

The Longfellow Bridge over the Charles River, nicknamed “The Pepperpot (or Pepper Pot) Bridge.

‘‘….winter drifts to where
The Pepperpot, ironic rainbow, spans
Charles River and its scales of scorched-earth miles
I saw my city in the Scales, the pans
Of judgment rising and descending. Piles
Of dead leaves char the air –
And I am a red arrow on this graph
Of Revelations. Every dove is sold.
The Chapel's sharp-shinned eagle shifts its hold
On serpent-Time, the rainbow's epitaph.’’

— From “Where the Rainbow Ends,’’ by Robert Lowell (1917-1977)