They are constructing just the one. I have heard nothing about two new towers going up. There was a competition to design the new tower or towers and the first link I posted is of the winning design. It is what will be replacing the twin towers.

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"...I won't be your winter...and I won't be anyones excuse to cry."

"Even heroes have the right to bleed."

"I'm wakin up at the start of the end of the world