Radiation victims further away from the explosion developed symptoms one to four weeks after the explosion. Within two or three days, radiation victims who were near the hypocentre developed symptoms such as nausea, vomiting, bloody diarrhoea and hair loss. Others with possibly less-fatal injuries died because of the breakdown of rescue and medical services, much of which had been destroyed, with personnel themselves killed. Many of those who survived the immediate blast died shortly afterwards from fatal burns. The death toll reached around 200,000 by the end of 1950. The total number of deaths was hard to establish, but at least 75,000 died in the first hours after the bomb was dropped, with around 140,000 dead by December 1945. Almost 63 per cent of the buildings of Hiroshima were completely destroyed and nearly 92 per cent of the structures in the city were either destroyed or damaged by the blast and fire. The firestorm created hurricane-force winds, spreading and intensifying the fire. In this area the immediate death rate was over 90 per cent. Beyond this central area, people were killed by the heat and blast waves, either out in the open or inside buildings collapsing and bursting into flame. All that was left of people caught out in the open were their shadows burnt into stone. Within a radius of half a mile of the centre of the blast, every person was killed. The heart of the explosion reached a temperature of several million degrees centigrade, resulting in a heat flash over a wide area, vapourising all human tissue. Unimpeded by hills or natural features to limit the blast, the fireball created by that single bomb destroyed 13 square kilometres of the city. The bomb, called ‘Little Boy’ because of its long, thin shape, was made from uranium 235. At quarter past eight on the morning of 6 August 1945, the US plane Enola Gay dropped an atomic bomb on the city centre, a busy residential and business district, crowded with people going about their daily business. The city of Hiroshima stands on a flat river delta on the Japanese island of Honshu.