Inscribed on the UNESCO World Heritage List in 1988, and on the List of World Heritage in Danger in 1990.
From the History Channel
Timbuktu was founded around 1100 C.E. as a camp for its proximity to the Niger River. Caravans quickly began to haul salt from mines in the Sahara Desert to trade for gold and slaves brought along the river from the south. By 1330, Timbuktu was part of the powerful Mali Empire, which controlled the lucrative gold-salt trade routes in the region. Two centuries later, Timbuktu reached its grandeur under the Songhay Empire, becoming a haven for scholars.
From the early part of the fourteenth century to the time of the Moroccan invasion in the late sixteenth century, the city of Timbuktu became an important intellectual and spiritual center of the Islamic world, attracting people from as far away as Saudi Arabia to study there. Great mosques, universities, schools, and libraries were built under the Mali and Songhay Empires, some of which still stand today.
Timbuktu's golden age ended in the late sixteenth century, when a Moroccan army destroyed the Songhay Empire. Portuguese navigators ensured Timbuktu's decline by establishing reliable trade with the West African coast and undercutting the city's commercial power. Around 400 years ago, European merchant ships began trading along the West African coast, and the cross-Saharan trade routes lost their importance. Having lost the source of its wealth, Timbuktu declined and became known as a lost city.
Today, the very fabric of Timbuktu today is threatened by what once contributed to the city's success—the Sahara Desert. The desert, which for centuries brought wealth to the city, now brings only drifting sands, driven by the dry wind of the harmattan, that threaten to smother the city and its monuments. This desertification has destroyed the vegetation, water supply, and many historical structures in the city. In response to the threat of encroachment by desert sands, Timbuktu was inscribed on the World Heritage List in Danger in 1990 and UNESCO established a conservation program to safeguard the city.