Documentary looking at the design and layout of the World Trade Center twin towers and considering the reasons why they both collapsed so quickly after terrorists flew two aeroplanes into them on September 11 2001. Includes input from engineers and those who designed and built the towers. Documentary looking at the design and layout of the World Trade Center twin towers and considering the reasons why they both collapsed so quickly after terrorists flew two aeroplanes into them on September 11 2001. Includes input from engineers and those who designed and built the towers. Documentary looking at the design and layout of the World Trade Center twin towers and considering the reasons why they both collapsed so quickly after terrorists flew two aeroplanes into them on September 11 2001. Includes input from engineers and those who designed and built the towers. Documentary looking at the design and layout of the World Trade Center twin towers and considering the reasons why they both collapsed so quickly after terrorists flew two aeroplanes into them on September 11 2001. Includes input from engineers and those who designed and built the towers.