The "great wall of sand" is a name used by the media for a series of land reclamation projects undertaken by the PRC since late 2013 in the South China Sea – particularly in the Spratly islands group – in order to strengthen PRC territorial claims to the region demarcated by the "nine-dash line". They are created by dredging sand onto coral reefs to create artificial islands which are then concreted to make permanent structures. By the time of the 2015 Shangri-La Dialogue, over 810 hectares (2,000 acres) of new land had been created. By June 2015, the land reclamation had reached 3,200 acres (1,300 ha) (13km2) (5 square miles).