Watch a gorgeous time-lapse of the Freedom Tower's construction

Much of Tuesday was spent looking back to the September day 11 years ago, clear and cool, until clouds of smoke and ash marred the sky as two planes crashed into the towers at the World Trade Center in Manhattan, killing nearly 3,000 and changing the trajectory of the United States.

Much effort has been spent to recover from the emotional, physical and economic damage wrought by al Qaida hijackers on September 11, 2001, and perhaps the most visible symbol of that recovery is the construction of the new One World Trade Center. Known also as the Freedom tower, 1 WTC has risen steadily since April 2006, ultimately reaching 1,776 feet upward into the sky. It's already the tallest building in New York, and will be the third-tallest building in the world at its final height.The new World Trade Center is due to open late next year, and external construction is nearing completion.

The webcam network Earthcam has put together a remarkable time-lapse of the tower's birth. It stands 105 floors high, as the final roof steel and antenna are still being installed, with the glass facade in place up to the 83rd floor.