This new 9/11 memorial features 40 wind chimes representing each victim who died September 11, 2001 on United Flight 93 https://cnn.it/2Omc6Br | CNN

When a plane hits the north tower of the World Trade Center, the first firefighters on the scene race against time to rescue the civilians trapped inside. Now, after almost two decades to reflect on the events that they lived through, we hear from eyewitnesses and first responders about what exactly happened on that fateful day in America. 9/11: One Day in America, premieres Tuesday 31st August at 9pm on National Geographic UK. | National Geographic UK