Click here to view picture gallery >>

On Sept. 11, 2001, after others hit the World Trade Center in New York City, a handful of Islamic terrorists hijacked a plane with 64 passengers and crew aboard and deliberately crashed it into this manifestation of American might. All aboard were killed, as well as 189 in the building. But also dying that day was the public's feeling of American invincibility and their sense of detachment from issues and conflicts on the other side of the globe.

In this, the first of two issues on the events since 9/11 at the Pentagon in Arlington, Va., and the World Trade Center, ENR commemorates the loss of life, property and innocence, but also celebrates the amazing response by the construction industry over the past year in repairing the Pentagon and clearing away over 1.5 million tons of rubble in New York ahead of schedule and under budget. ENR will cover the rebuilding of lower Manhattan in a special report in the Sept. 9 issue.

The lessons learned at the Pentagon on 9/11 will change forever the design and construction of high-risk structures or those with special vulnerability. Designed to be a temporary structure and constructed in an amazingly fast 16 months during the darkest days of World War II, the Pentagon at the time of the 9/11 attack had been undergoing a massive renovation that included "hardening" the structure against terrorist and other kinds of attack. Little did the planners, designers and contractors know that 9/11 would move the testing of their work from sanitary computer simulations to the crucible of a fanatical attack.

The plane hit the Pentagon at a point where a recently renovated "wedge" adjoined another with original construction. The blast-resistant windows, Kevlar armor and structural reinforcement and firewalls added in the renovation saved the lives of many building occupants and provided a stunning side-by-side testing of materials and design that no one ever really wanted or expected to see.

This kind of protection works. One only has to look at the collapsed portion of the Pentagon and the adjacent battered, burned but standing section to assess the chances of survival for occupants.

From ruin and heroism on 9/11, the construction industry in only a year has restored the gap in the Pentagon's facade and the nation's confidence. Tenants are moving into the reconstructed section and the renovation of the remaining unscathed wedges has been quickened.

Although a sense of normalcy is returning at the Pentagon, nothing ever will really be the same. The restored walls once again give it the imposing appearance of the five-sided fortress that it really is. From those walls have gone the orders for America and its allies to strike back at the terrorists in their lairs in Afghanistan and elsewhere.

There have been successes and setbacks in this effort to root out those who would prey on innocents, but at least the American people now understand that they are at war and that the enemy is among us. Sacrifices will have to be made, both in lives lost and the way we live. In only a year, the issue of Homeland Security has moved to the forefront and those initiatives already have changed the way we think, travel and build. And the battle has just begun.

t its heart, the Pentagon is just an office building, although it is the world's largest at 6.5 million sq ft. But in the hearts of the American people, it is much more–a symbol of the might of the U.S. military. The structure's symbolism is so strong and enduring that the U.S. Dept. of Defense often is referred to by the name of the building its workers occupy.