9/11 Rebuild timeline.

Sep 11, 2001

9:59 am - The South Tower of the World Trade Center collapses.
Sep 11, 2001

10:28 am - The World Trade Center’s North Tower collapses, 102 minutes after being struck by Flight 11.
2002

One World Trade Center Design Competition

The original design by Daniel Libeskind, the winner of the competition, was heavily altered to a more traditional profile design with simple symmetries. http://www.koebogen.info/wp-content/uploads/koe-bogen_architektur_LAY_2.jpg
Dec 19, 2003

Unveiled the Concept for the One World Trade Center

The footprint of the cubic base is identical to those of the previous Twin Towers.
Apr 28, 2006

Construction Officially Begins on the One World Trade Center
Dec 19, 2006

First Steel Columns for the One World Trade Center are Placed

http://i.dailymail.co.uk/i/pix/2012/04/30/article-2137005-12D9A9F7000005DC-115_964x625.jpg
2008

First Installation of Memorial Steel

http://static5.businessinsider.com/image/501f525eeab8ea8e37000004/obama-one-world-trade-center.jpg
Nov 3, 2014

One World Trade Center opened for business
May 29, 2015

One World Observatory opens to the general public May 29, 2015

9:59 am - The South Tower of the World Trade Center collapses.