Francesc Torres explains the story behind his photographs of objects recovered after the attacks on the World Trade Centre; from his exhibition Memory Remains, Imperial War Musuem, London. To view more Economist articles relating to 911 go to: br Subscribe NOW to The Economist: br Get more The Economistbr Follow us: Like us: View photos: br The Economist videos give authoritative insight and opinion on international news, politics, business, finance, science, technology and the connections between them.