On 11 September, memorial events took place around the US to mark 20 years since the largest terrorist attack in the US. On 11 September 2001, 19 members of the terrorist group al-Qaeda hijacked four aeroplanes, two of which crashed into the World Trade Center’s Twin Towers, two skyscrapers in New York where 50,000 people worked. The third plane flew into the Pentagon, the US military headquarters, and the fourth, which was going to Washington D.C. (the capital of the US), crashed in Pennsylvania. In all, 2,977 people died, including firefighters who ran into burning buildings to help people.
To mark the anniversary, there was a ceremony at Ground Zero, the site where the Twin Towers stood. The names of the victims were read out, a tradition that takes place…
