The building will be more than 17 hundred foot high once it’s finished next year. That’s more than 300 feet taller than Willis Tower.
Council Director Anthony Wood says it came down to one design aspect.
"The spire on top of One World Trade Center has been designed architecturally, and it holds a beacon. That’s what the committee took into account when counting the spire on world trade center and not counting the antenna on Sears."
Without the spire, One World Trade Center would be 100 feet shorter than Willis Tower.
Meanwhile, Chicago Mayor Rahm Emanuel is scoffing at the ruling that bumps Willis Tower to the Number Two spot. He suggested the World Trade Center’s spire should NOT give it a competitive edge.
"If it looks like an antenna, acts like an antenna, then guess what? It is an antenna. That’s No. 1. No. 2: I think that at the Willis Tower you will have a view that is unprecedented in it’s beauty, in its landscape, in its capacity to capture something - something you can’t do from an antenna."
Under Tuesday's ruling, the Willis Tower will still be in the top ten tallest buildings in the world.