There is a hole in the heart of America that is as big as the World Trade Center towers were tall. A year ago, terrorists struck at what they thought was the symbol of American business. That they succeeded in bringing down the twin 110-story skyscrapers that had defined the New York City skyline for 30 years is a testament to their determination, their hatred of America and their willingness to sacrifice their lives and the lives of almost 3,000 innocent people. But they were mistaken in their belief that their action could seriously damage or weaken a nation and government of the people by the people and for the people. Click here to view picture gallery >>

America has endured greater tragedies than the Sept. 11 attacks in our 226 years as a nation. There has been greater bloodshed in natural and man-made disasters, and there has been greater economic loss. But the events of Sept. 11 rise above many of the others because they were deliberate and caught the American people by surprise, just as the Japanese attack on Pearl Harbor did in 1941. In both cases, the nation had the opportunity to prevent the attacks, but ignored or downplayed the threat. In both cases, life in America afterward was never the same.

If anything, the attacks on the World Trade Center and Pentagon have brought America together in ways that the terrorists could not have imagined in their fog of religious and political zeal. The construction industry responded immediately and heroically to assist in the recovery of the dead and injured and later in the removal of about 1.5 million tons of debris. They worked in exceptionally dangerous conditions, yet there were so many volunteers that they had to be turned away in droves.

The nation also came together in recognizing that it was at war and actually had been since the first attack on the World Trade Center in 1993. If that recognition had come sooner, many of the initiatives taken later under the Homeland Security push might have thwarted the attacks.

Now that they are down, the World Trade Center towers have taken on a greater symbolism and significance than they ever had in life, for they were not universally loved while they stood. The people who died there came from all walks of life and were not a military target by any stretch of the imagination. Such is the way of cowardly terrorists and religious fanatics.

While the attack on the Pentagon has stimulated debate over design, materials and construction techniques to harden critical structures from attack, the World Trade Center has ignited discussions on whether supertall structures are viable, how to effectively evacuate people from high-rises and how to mitigate the risk of collapse after a devastating event.

The towers are gone and even the massive space they once occupied is causing hand-wringing over the state of land-use planning for urban environments. The 16-acre site sits in the midst of some of the most densely developed real estate on the planet and the volatile mix of politics, money, emotion and art may yet cause another explosion over what to do with it. Some want the towers rebuilt, some want smaller structures and still others want a mega-memorial.

The array of buildings and the amount of public space in the redevelopment may be open to debate, but everyone agrees that there must be a memorial at the site so that the nation may remember and reflect on what happened for generations to come. The size and shape of this is yet to be determined, but not the significance.

As Abraham Lincoln eloquently said in his Gettysburg address: "…we cannot dedicate, we cannot consecrate, we cannot hallow this ground. The brave men, living and dead, who struggled here have consecrated it far above our poor power to add or detract. The world will little note nor long remember what we say here, but it can never forget what they did here."