In the face of an immense tragedy it is always extremely hard to find the right words to express your feelings. Even twenty years after the 9/11 attacks, we all feel inadequate and watching footage of the Twin Towers collapsing still proves utterly shocking.
The stories of the four coordinated terrorist attacks by the militant Islamist terrorist group Al-Qaeda against the United States that occurred in September 2001 – with two commercial aircrafts flown into the twin towers of the World Trade Center in Lower Manhattan, another plane hitting the Pentagon in Arlington, Virginia, while the fourth crashed into a field in Pennsylvania – can be told from different points of view, through the stories of the rescuers, the survivors or the families of the victims for example, but the attack on the World Trade Center (WTC) is also a story of architecture and engineering.
One documentary that we reviewed three years ago, "Leaning Out" by Basia and Leonard Myszynski, goes through the events from a technical point of view. The story of engineer Leslie E. Robertson, "Leaning Out" features long sections about the planning, construction and collapse of the World Trade Center.
Robertson, who died in February this year, was selected by Worthington, Skilling, Helle, and Jackson (WSHJ) to participate in the design of the 110-story WTC towers, a project conceived in the '60s and completed in 1971.
The project was long and challenging and Robertson spent a long time doing a series of wind tunnel studies with models to research issues of elasticity, but also put people in motion simulators to see how they reacted.
Dampers were eventually integrated in the structure to absorb the swept of the wind, while narrow windows delineated by structural elements around the perimeter were favoured as they offered people working in the building a heightened sense of safety thanks to the closely spaced steel pipes. Load-bearing columns were placed around the perimeter of each building, a solution that allowed engineers to eliminate all columns within the office space. Robertson considered what may have happened if a building had been hit by a plane, but he designed the towers to withstand a Boeing 707 and not two fully-fuelled 767s travelling at hundreds of miles an hour.
On 9/11 Robertson was in Hong Kong and followed the events on TV: the planes that crashed on the Twin Towers hit a number of external columns, the gravity loads were redistributed, but jet-fuel fires spread through, affecting the steel that rapidly lost its strength. The buildings couldn't stand the load anymore and collapsed, killing 2,754 people (the overall death toll of the four coordinated attacks was 2,996).
The leading structural engineer behind the WTC complex, known for his humanity and commitment to pacifism, was deeply shaken, devastated and traumatised by the event, and started feeling guilty and responsible for what had happened.
Following the events the authorities contacted the offices of Robertson, to study how the structures had been designed, understand the causes that had brought to their collapse and locate survivors or missing people. Investigations eventually proved that the way the towers had been built gave time to some people to safely evacuate the buildings.
After the attacks many wondered what was the future of dense cities, office working and skyscrapers, but, when Daniel Libeskind became the master plan architect for the reconstruction of the World Trade Center site, and when "Reflecting Absence", a Memorial by architect Michael Arad with landscape architect Peter Walker, was chosen for the site where the Twin Towers once stood, a new component entered the "architecture and design" equation – meditation in public spaces.
Set in the centre of the Memorial Plaza and surrounded by white oaks, "Reflecting Abscence" comprises two pools recessed thirty feet into the ground and lined by waterfalls that make the abscence present and visible, while the names of the victims are incised into the panels surrounding the waterfall.
Memory merged in this way with architecture and a commercial site was turned into a memorial; a global finance district was transformed into a sanctuary, reminding us that architecture has a healing role and can help us highlighting the importance of poetry and contemplation in life.
While researching the area, the architects involved in the reconstruction of the WTC realised indeed that this wasn't just a urban area in the middle of a vibrant city, but it was a sacred space where thousands had died and where many bodies were never recovered.
The Coronavirus pandemic has prompted us to look at new architectural challenges, from health structures and hospitals to temporary vaccination hubs, but it has alerted us all also to the spiritual needs of our communities and to the importance of creating civic spaces where we may be able to peacefully ponder and reflect about our lives and, possibly one day soon, celebrate the end of the global pandemic.
Arad, for example, developed an idea for a memorial project to the pandemic years: located in the middle of the Jacqueline Kennedy Onassis Reservoir in Central Park, it features a temporary island that becomes accessible once a year when the water level in the reservoir falls to reveal a submerged stone dam that runs the length of the reservoir from north to south.
This memorial should be a space for the living to reflect on the impact and losses suffered during the Covid-19 pandemic and find solace in the company of others, a key feature after a time of isolation and loneliness. We can only hope that planners will start dedicating more spaces in our complex urban world for places where people can perform modern spiritual and personal rituals in a quiet and healing environment.
Image credits for this post
1. Twin Towers in orange light. Courtesy Leslie Robertson
2 – 4. The Twin Towers after the 9/11 attacks. Photo by Jan Szumanski
5. Leslie Robertson by a steel beam from WTC in the documentary "Leaning Out", 2017. Photo Credit: Leonard Myszynsky
6 – 8. National September 11 Memorial, New York by Michael Arad
9. Covid-19 memorial by Michael Arad