CAIRO: The Egyptian Housing and Building National Research Center is hosting the fourth International Conference for Administration and Eco-planning entitle "the Green Cities, a way to sustainability." The conference is to be hosted on December 10 to 13 in the headquarters of the Center in the district of Dokki in Giza. Meanwhile, the Center is preparing to hold a symposium entitled “Productive, low-priced and eco-friendly village" on Thursday December 8. The symposium will tackle techniques of modern building in green and eco-friendly architecture.