These lines describe the loss of the identity of the city though the loss of the empire state buildings.
Step-by-step explanation:
The world trade center ad the twin towers of the empire state building had been the center and the symbol of US commerce for a long time and were a reminder of its financial power.
They were attacked and torn down and thus the poem concerns with the twin towers.
The poem talks from the perspective of a bird in the sky or perhaps anything in the skyline that misses the grandeur of the two buildings talking about the loss of what was unthinkable to lose.