A resident and his dog in Comuna 13, once considered the most dangerous district of the city, in 2006, the city built a public library, a new school, public green spaces, and improved access to transportation through a cable car line and escalators connecting the neighbourhoods to the metro and the city.To implement these changes, the military and paramilitaries carried out 17 operations to drive out the leftist guerrillas that once controlled the district and the main highway that connects to the coastal ports. In 2002 the final military deployment, Operation Orion, killed 17 people. Throughout these operations, hundreds of residents were disappeared and were caught in the deadly crossfire between police, army, paramilitary and guerillas. Comuna 13 is the only district with a military base from where the army regularly patrols the area. In recent years the city has been transformed using a model city authorities have named 'social urbanism'. This involved heavy investment in the city's poorer areas, education and business development and its urban transportation system. The murder rates have dropped ten fold and the city, although not without serious issues, has been acclaimed worldwide for its innovation and social progress. Despite all the improvements, Medellin's residents continue to be displaced from their homes by inner city drug gangs and a half century of war, the world's longest lasting current conflict.