Some behind-the-scenes information about rebuilding where the twin towers stood.
AP via Yahoo! News
The steel bound for the Freedom Tower at ground zero travels thousands of miles, from a plant in Luxembourg where columns are rolled through casting machines at temperatures approaching 2,340 degrees.
Scrap metal melted into liquid steel in an electric furnace is cast, heated, cooled and heated again at the ArcelorMittal steel mill in Differdange.
The steel makes its way to a plant in Virginia where the huge columns are cut to size. Eventually, it is shipped to New York City, where the columns are lifted by crane and painstakingly set on top of each other at ground zero.
The jumbo steel columns — foot by foot, ton by ton — are forming the skeleton of the 1,776-foot Freedom Tower, designed just after the 2001 attacks to replace the destroyed World Trade Center. Each column makes a 4,700-mile journey, taking weeks and sometimes months to arrive at ground zero.