New York (CNN) - It has risen - floor by floor, gleaming steel beam by steel beam - from the scene of what was incomprehensible destruction more than a decade ago.

Now, as 1 World Trade Center in Lower Manhattan stretches closer toward being the tallest building in the United States, it already stands as an icon in its own right.

Punctuating the Manhattan horizon, the once-named "Freedom Tower" also was once fraught with controversy and costly redesigns. But it's soon expected to top off at 1,776 feet - technically edging out the Willis Tower in Chicago by way of decorative spire affixed to its peak, and replacing the Twin Towers that fell to terrorist attacks on September 11, 2001.

Crews at the site are gearing up for President Barack Obama's visit Thursday to the work-in-progress - which now has reached 104 stories - for an update on its upward growth. The president will tour the site and sign a beam to be placed at the top of 1 World Trade Center. The building is expected to open in about a year and a half.

CNN's Poppy Harlow previews the President's visit today.

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