Timbuktu is an ancient city in Mali located on the Niger River that served as an important center of Islamic learning between the 12th-16th centuries. It contained several historic mosques and madrasas that established it as a scholarly center. In 1988, parts of Timbuktu's historic center were inscribed as a UNESCO World Heritage Site for their cultural and architectural significance. However, the site was later placed on UNESCO's List of World Heritage in Danger due to threats of new construction and desertification.