What is Ground Zero, the memorial that fills the “hole” left by the twin towers on 11 September 2001

On the morning of Tuesday 11 September 2001, two scheduled planes, belonging to the major American airlines (United Airlines and American Airlines) were diverted by a group of terrorists belonging to the terrorist organization Al Qaeda. Flight American Airlines 11 and the flight United Airlines 175they were respectively crashed on the north tower and on the south tower of the World Trade Centerin the Lower Mantthan neighborhood in New York. Within 1 hour and 42 minutes, Both twin towers collapsed. This attack, together with two other hijacations that took place on the same day, caused the death of almost 3,000 people. Today, to commemorate the memory of the fallen of 11 September, at the exact point of the tragedy stands the National September 11 Memorial & Museum or “Ground Zero” – Literally “zero level”. Built on the foundations of the towers, it has different areas including the Memorial Plazaa space with two huge tanks 9 meters high (30 feet) that follow the perimeter of the towers, equipped with artificial waterfalls and edged by bronze panels with engraved the names of the victims. Below the memorial is the museum, which houses numerous symbolic finds, including the “Last Column” and the remains of a fire truck.

The National September 11 Memorial & Museum in Ground Zero

The National Septeber 11 Memorial & Museum It is a complex that makes tribute to the memory of the over 2900 deaths of the attacks of 11 September, and those of the attack of the February 1993. The site where the memorial was made is called Ground Zero. The term derives from military jargon, and indicates the exact point where a bomb, in particular a nuclear bomb, explodes. The choice to use this name to indicate such a place is aimed precisely at transposing the sense of tragedy of events and devastation.

The project consists of different areas, or sectors. The Memorial Plazacreated according to the project Michael Arad And Peter Walkewas built instead of the foundations of the twin towers, is an area of 8 acres (3,237 Ettari) on which 400 oak trees were planted. The outdoor memorial was designed to offer a silent space, aimed at contemplation. At the center of the memorial there are Two huge tankswhose perimeter is exactly the one occupied by the two towers, each of which occupies an area of ​​almost 1 hectare. The two swimming pools have been conceived and make in order to host the largest artificial waterfalls in America. These are two high chasms 9 meterson whose edges, names of the 2977 victims of 90 different nationalities. We wanted to give the impression that the water would fall into the void, without ever stopping. This requested the adoption of a complex water collection and drainage system, including a face heating system and prevent the water from fulfilling the colder months.

One of the most particular, and certainly commemorative elements, is certainly the Survivor Tree. It is a tree of Pero that has been recovered by the rubble, treated and made growing, and planted in the memorial, to symbolize the resilience of the American people towards such vile attacks.

The 9/11 Museum

Under the memorial the Museum of attacks on 11 September. Inside the museum there are many deeply symbolic objects. One of the most important “Last Column”, the last pillar removed from the place of attacks, together with a fire truck destroyed. Another interesting engineering element is the “Slurry Wall“, An reinforced concrete wall that avoided that the site was flooded during the flooding of the Hudson river. This wall was already part of the World Trade Center complex and was” recovered “as an integral part of the museum.

Among the main challenges that the engineers faced in the construction of the museum. The space available was little, and the engineers also found themselves having to face the presence of other important infrastructure elements such as the subway right at the point where the entrance should have been made. This led the designers to choose to support the entire structural deck in just 12 points, exploiting the roof of the museum as a side support.

In this place, every year, the American government organize commemorative eventsaimed at not making the memory of the attacks lose and to explain to the youngest what was on 11 September.

The twin towers

The attacks on the World Trade Center were perpetrated against the two major towers of the entire WTC complex, made up of 16 towers, mostly designed by the architect Minoru Yamasaki and by the engineer Leslie Robertson. The two towers were, in fact, the symbol of the WTC, and were inaugurated on April 4, 1973.

At the time of their completion, the two towers were the highest buildings in the world, with theirs 417.5 m The north towerAnd 415 m the south tower. The total area of ​​both towers was 800,000 square meters, and the two towers had a total of 196 lifts.