Timbuktu is a UNESCO World Heritage Site since 1988. In 1990, it was added to the list of world heritage sites in danger due to the threat of desert sands. A program was set up to preserve the site and in 2005, it was taken off the list of endangered sites. It was one of the major stops during Henry Louis Gates' PBS special "Wonders of the African World". Gates visited with Abdel Kadir Haidara, curator of the Mamma Haidara Library together with Ali Ould Sidi from the Cultural Mission of Mali. It is thanks to Gates that an Andrew Mellon Foundation Grant was obtained to finance the construction of the library's facilities, later inspiring the work of the Timbuktu Libraries Project.