More than 4000 physical structures were destroyed or damaged in Port-au-Prince, Haiti, by the magnitude 7 earthquake that struck the country on 12 January 2010. About 2000 residential buildings have partially or totally collapsed and the same number of buildings shows severe damage. A number of critical infrastructures such as government buildings, educational structures and hospitals have collapsed or are severely damaged. These are the preliminary findings of a rapid damage assessment carried out by the JRC based on the analysis of very high resolution satellite imagery acquired before and after the disaster.