The sight of thousands of passengers in the long lines at Heathrow Airport, JFK, and LAX, snaking through the arrival halls or waiting patiently outdoors in rain slickers on August 10 produced a familiar kind of dread mixed with acceptance: Since September 11, 2001, our world has irrevocably changed. In assessing the implications of the attacks on the World Trade Center and the Pentagon, we find that—besides the discussions and plans for the affected sites and their memorials, and our new awareness of the elevation of architecture in the popular consciousness—the aftermath of those events has provoked spirited debate and sometimes transformation in the built world. Five years later, we ask, have we in fact progressed toward safer, healthier spaces?

To judge from the expressions on the faces of the waiting public in the airports, not much. Despite massive investment in airport security, including computerized baggage screening, various metal and trace explosive detectors, surveillance and perimeter intrusion systems, we still have no effective way of pinpointing liquid, peroxide-based explosives in our airports. So-called “puffer” technology, which emits bursts of air to find explosive traces on clothing, comes at a high price and takes up more precious space. Nor do we have guarantees that terrorists would not find other ways of slipping through the permeable borders that airline terminals, not to mention rail centers and ports, represent.

With all our investments and all our cleverness at tightening things up, we remain vulnerable. Aviation Week and Space Technology recently reported that if the perpetrators of the recent airline plot in Britain had managed to secrete the liquid materials among their possessions, they might well have slipped through security and boarded their intended flights. Another new gadget might have helped, but there is no guarantee.

As a culture, we have relied on technology to solve problems sometimes better solved by people. Investigators, real people using human intelligence, not electronics, cracked open the plot, exposing the intentions of more than 20 persons to blow up planes of four different airlines before they set foot in an airport or entered the area we call “security.”

What can we learn from these experiences, and how can we architects make a difference? The shift in tactics by a dangerous few has implications for architects worth considering. First, the dynamics of security in the post-9/11 world requires nimbleness of response. Yesterday’s norm, a bottle purchased in a duty-free shop, becomes tomorrow’s incendiary device. Marilyn Jordan Taylor, FAIA, who has led major terminal design teams at Skidmore, Owings & Merrill, places the burden on design professionals not only to “understand operations and security” at airports, but also “to provide acceptable, understandable experiences for passengers.” If others control security, architects control the experience, she postulates.

In a world with increasing surveillance, a world that sometimes feels as inescapable as the terminal in Steven Spielberg’s film of that name, we may face other days similar to August 10, despite our collective efforts. Will architects have provided pleasant places for queuing? Places of rest or peace in the hubbub? Opportunities for the elderly or the weary to sit? Changes in lighting levels, in perspectives, in coloration? While we will inevitably require chokepoints for maximum scrutiny, can we also provide comfort, settings that minimize fear and maximize our awareness of personal space and of individual self-control? And what to make of cell-phone-infested waiting areas?

For those relatively few architects tasked with upgrading existing terminals or building new ones, we can segregate movement systems in a way that effectively separates cars and people, that minimizes feelings of anxiety caused by crowding, and that still gives us a sense of arrival and possibility that travel suggests. Airports, like the rail terminals that preceded them, remain primary points of embarkation and arrival, now stretched to the global scale.

What have we learned in five years? Machines may give us the illusion that we are actively solving the security problem, but the human mind, the most remarkable machine, deserves our full attention as architects. While we may not be security experts, shaping the character of human behavior in public space lies squarely within our hands, an ability undetectable on anyone’s screening system.