Twenty years later: why the 9/11 twin towers collapsed

The video explains the structural integrity of the World Trade Center, focusing on its vertical and horizontal load management systems. It describes how the core of reinforced concrete and steel pillars worked together to support the building. The National Institute of Standards and Technology (NIST) report is discussed, detailing how the impact of the planes and subsequent fires led to the collapse of the towers. The report highlights the role of structural steel weakening and the inability of lower floors to resist the energy of the falling structure.

What was the outcome of the National Institute of Standards and Technology's report on the buildings?

What role did the floors below the impact zones play during the collapse?