[Veto!]

Yikes, what is that minarettish thing on top?

[Jim from C-Town]

That is what modern communication towers look like. Being that the building is so tall, the entire top is brimming with antenna equipment. Every cell phone company, radio station, communications company and enterprise, including the government, that has satellites and the need to communicate with them want to have space on the highest building in the most wired city in the World.

[Yossarian]

That's the antenna tower. It was supposed to be covered by a fiberglass "radome", which would give it more visual heft, while still allowing the antennas to work.

The radome was budgeted as costing $20 million. (which means: it really should of cost $5 million, but with cost overruns, it would actually cost $30 million.)

However, once Skidmore Owings & Merrill took over the cost management of the building, they ditched the radome to save money. You can read about it at this WSJ article.

When you consider what this ends up making the building look like, plus the fact that it may put the overall "official" height of the building at risk, maybe New Yorkers can start a petition / funding drive to get the radome added back to the One WTC....

[lacrew]

I assume its an antenna...and its shaped that way because...well...I guess the antenna works better with that shape...?

Or its just exactly what it looks like.