1 day: Lights go out on the tower forever.
6 months: After half a year without maintenance, the once-elegant tower isn't looking so pretty. The windows have become green and grimy, and the steel has corroded.
3 years: Glass has broken and the building begins to waste away. After a flood, the first four floors of the tower have been flooded, and the foundations are disintegrating.
70 years: The spire buckles and falls to the ground.
110 years: After a hurricane even worse than Sandy hits NYC, the bottom floors disintegrate. The tower leans on nearby buildings, and can no longer stand on its own.
250 years: The entire structure is destroyed by harsh weather and corrosion.