The 9/11 tragedy involved three sites: New York City, The Pentagon (Washington D.C.) and Pennsylvania. Because of the bravery of the passengers who fought back against the highjackers, the Pennsylvania crash site did not involve any heavily populated city or government building. The Pentagon 9/11 damage was repaired and rebuilt over a period of eighteen months. All tenants were back in their offices by February 2003.
Did you ever wonder why it has taken 10 years to rebuild the Ground Zero (New York) site and it is not finished yet? When you visit the area, one thing you recognize is it’s located in the middle of the downtown Manhattan (only a few blocks from Wall Street, our financial center). Just removing the debris from the site took months and years and it all had to be trucked and ferried away from the area (remember, Manhattan is an island). Also, the World Trade Center Twin Tower buildings were located on top of the Path commuter train/subway transportation hub. Several stories of below-ground building and infrastructure had to be dealt with before rebuilding could begin. For several years, discussions went on as to what to do: build or not, leave the site open as a memorial, etc.
I personally like what the builders are building. When One World Trade is finished, it will soar 1776 feet in the New York skyline and be the tallest building in America. The memorial pools/waterfalls are located on the footprint of each WTC twin tower building as a memorial site. The trees in the memorial park were moved from the Pentagon and Pennsylvania crash sites. All these symbols fit together so nicely.