They call this as The Last Column of the Twin Towers. It is called so because it was the last column standing that was removed from the Ground Zero, where the Twin Towers used to stand tall and proud. When the workers and rescuers pulled it out from the ground, they wrote (or vandalized?) it with prayers, words of sympathy, endearment, hope and remembrance for all the victims of the 911 terrorist attack.
When you visit the 911 Memorial Museum, you’ll see “The Last Column” conspicuously standing in a spacious lobby among other ruins of what was left of the Twin Towers.
Buy your tickets online and choose the time you like. It is much easier and faster that way, especially when the queue is unbearably long in summer. Allow two to three hours inside the 911 Memorial Museum.