World Trade Center Ruins

The most dramatic ruins that any of us will ever (hopefully) see were the ruins of the World Trade Center, destroyed on Sept. 11, 2001 by two commercial jets. The story is well-known, so I won't recount it here.
I remember the day very well - I was on campus at the University of Michigan in Ann Arbor. I left for class on North Campus early that day, because I needed to buy a blue book for an upcoming exam. At the checkout counter, a radio was on and we heard a news bulletin that an airplane had flown into the World Trade Center. At the time the newscasters believed that it was a small propeller plane.
I continued to North Campus, and because I had a few minutes until class, I stopped in the computer lab and opened up cnn.com. There again I saw reports about an airplane, but still it wasn't clear and didn't seem like such a big deal. I walked out of the computer lab, and noticed that one of the larger classrooms was packed with students and a projection screen was pulled down. A live broadcast of the WTC was being shown, and moments after I walked in, the first tower began to collapse. (It was at 9:59 am, and class was set to begin at 10:10). That was when I realized the enormity of the situation. Class never happened, and I went back to Central Campus. On the bus ride back students who hadn't heard were asking what was going on, and at one point I told someone that the WTC had been attacked and collapsed, and that classes were canceled.
I didn't have a television that year, so I went to the grad library where some t.vs had been set up and they were showing coverage. I sat on the floor, cross-legged, for about 4 hours, watching with other students. At some point I went home. Classes were canceled the following day as well.

In the New York: A Documentary Film episode "The Center of the World," Ric Burns interviews a number of people regarding the destruction of the World Trade Center. Two interviews caught my attention:

Kenneth T. Jackson: "Well, I think one of the sad things to me is to remember the enormous human effort that went into building those buildings, the gigantic endeavor, the thousands of construction workers, the millions and millions of man hours and effort, and how quickly it could all be torn down. The fact that just this physical creation, you know, could be destroyed that took years and years and years to do, to conceive, to plan, to execute. I guess, again, it's like us, you know. We're, it takes us a lifetime to create the person we are and can be wiped out in a single mistake or accident. And so it is with cities and buildings."

William Langewiesche: "I think it's precisely like death. I mean, death of someone you know or someone you love. I don't [know how] many people loved those buildings, but certainly a lot of people knew them. And then they were gone. I mean, how can it be that something that extreme can happen so quickly and so irreversibly? Can't we just kind of reel that backward a little bit? No, we can't. We can't do it any more with those buildings than with death, and I think the emotional reaction is very similar. This was a public death."

Here we have two different takes on the destruction of the building. One thinks about it in terms of vanitas - all the hard toil that it took to build the World Trade Center, undone in an instant. The other connects it with death.

A design competition was held for a memorial at Ground Zero, and the winner was actually an Israeli, Michael Arad, and famed landscape architect Peter Walker:

"The Memorial will consist of two massive pools set within the footprints of the Twin Towers with the largest manmade waterfalls in the country cascading down their sides. They will be a powerful reminder of the Twin Towers and of the unprecedented loss of life from an attack on our soil. The names of the nearly 3,000 individuals who were killed in the September 11 attacks in New York City, Pennsylvania, and at the Pentagon, and the February 1993 World Trade Center bombing will be inscribed around the edges of the Memorial pools."

Although the memorial is on the site and creates a hollow where the buildings once stood, it doesn't really make use of the ruins of the building. However, very soon after the event, New York started giving out pieces of the rubble to towns and cities around the world to incorporate into local 9/11 memorials.

Another piece of rubble, akin to the cross found in the bombed-out Coventry Cathedral, was shaped in a cross. Like in Coventry, the cross was set up on site and was later reused. It should also be noted that some of the steel from the WTC was recycled and used for an new U.S. battleship.