The Sahara is the largest desert in the world spanning over 3.5 million square miles. While it has been a desert for millenniums (thousands of years), there have been two periods of time in the last 12,000 years that the region received rainfall and became habitable.

While Scientists have suspected that two distinct civilizations inhabited the area during this period, thery had very little evidence.

Then recently, Paul Sereno and his team from the University of Chicago searching for remains of dinosaurs in the Niger, Africa, stumbled upon an amazing discovery - A cemetery of over 200 graves with the skeletons in almost perfect condition. In the same area, they also found remains of animals, like large fish and crocodiles that could have never survived in the modern Sahara. In addition to the remains, the paleontologists found remains of tools, pots and other artifacts - all indications of the civilizations that once lived in the now arid region.

It was about 12,000 years ago when a slight tilt in the Earth's orbit, coupled with other factors, resulted in rain in the Sahara, making it habitable, from Egypt in the East, to Mauritania in the West. 4,000 years later, the rains stopped and the Sahara became dry again. After 1,000 years, the cycle repeated itself and the region became habitable for two more millenniums, bringing with it a totally new civilization.

The cemetary found was apparently used as burial grounds by both the civilizations. The first group that lived in the area, when it was at its wettest, between 8,000 to 12,000 years ago, called Kiffians were tall, powerfully built hunters and fishermen. The second group, known as the Tenerians were smaller in size and lived off fishing, hunting and cattle rearing.

The remains that have been discovered are surprisingly intact. One of the most amazing ones is that of a mother (first picture above), buried under a bed of flowers with her two children. Not only are the skeletons intact, but scientists also found pollen from the flowers. In another, the arm of a young girl (pic on the left) is still adorned with a hippo bracelet she was buried with.

The research on the civilizations is not done yet, as the team continues to examine the bones to try get more details about the health and diet of these people. A bigger expedition is currently being planned to the area to further explore the two civilizations.

To read more about this amazing discovery and watch a video click on this link to the National Geographic article. http://news.nationalgeographic.com/news/2008/08/080814-sereno-sahara-missions.html

Sources: National Geographic, DailyMail.co.uk,Los Angeles Times