A review of progressive collapse and the various factors which cause it has been brought in this paper. Progressive collapse of a building can be referred as the situation where the local failure of a primary load bearing or structural component lead to the collapse of the adjoining member and to an overall damage of the structure. It has been figured out that buildings which were built as per current design codes were not robust enough under the action of accidental load and it failed progressively. Progressive collapse is not proportional to the original local damage. This phenomenon is also called as disproportionate collapse, for the reason that the collapse is out of proportion in comparison to the original triggering event. Progressive collapse occur when one or more vertical load members particularly columns are damaged during extreme events (i.e. terrorist attacks, fire, explosions, vehicle impacts etc.). When a column is failed the gravity load of the building is transferred to the adjoining members of the structure and if the other members of the structure are not properly designed to bear and redistribute the additional loads, then the substantial part of the structure may collapse thus causing greater damage to the structure than the initial impact. It is always accompanied by serious personal and material losses. Since the start of the 21st century there has been growing interests in the risks associated with extreme, especially after the attacks on the Alfred P. Murrah Federal Building in Oklahoma in 1995 and on the World Trade Centre in New York in 2001. Because of these collapses which have led to a huge loss of life and property, the idea has become accepted worldwide that there is a need for robust structures which can bear/sustain local failures with suffering progressive collapse.