Facts About Deserts
The word Sahara, the name of the great desert in the north of Africa, comes from the Arabic sahira, which means "deserts," "wastes," or "wilds." So, saying "Sahara desert" is redundant. (source)
The Sahara, the world's largest desert, is not the largest sand desert. Only 15% of the Sahara is sand dunes, while over 70% consists of stone desert. The largest sand desert is the Great Arabian Desert, or Rub-al-Khali, in the Arabian Peninsula. (source)
As recently as 5,000 years ago, the Sahara was a lush savannah that was home to elephants, giraffes, hippopotami and antelopes. It is believed that the Sahara will become green again in around 15,000 years due to changes in the Earth's tilt. (source)
Several of the Lakes of Ounianga.
There are freshwater lakes in the Sahara, the Lakes of Ounianga in Chad. (source)
The Atacama desert, along the Pacific Ocean in Chile, is the driest place on Earth. Prior to a freak storm in 1971, no significant amount of rain had fallen on the desert in 400 years. There are still some weather stations in the desert that have never recorded rain. (source)
In 582, it rained "blood" on Paris. The terrified population believed this to be a sign of divine displeasure, and replied by indulging in an agony of repentance. The true cause of this weird event was the sirocco, the wind that sometimes blows from the Sahara across the Mediterranean into Europe. It is laden with a fine red dust from the desert interior, and this had dyed the rain that fell on Paris.
The oldest desert in the world is the Namib Desert in Namibia, which is believed to have been arid for the past 55 to 80 million years. (source)
Europe is the only continent without any deserts.
Thirteen percent of the world's population lives in deserts, which account for about one-third of the Earth's land surface.
In the Pampa Colorada (Red Plain) in the Peruvian Desert, there are large line-drawings of geometric shapes, animals and plants on the desert soil. These drawings are known as the Nazca lines. These were likely drawn by the Nazca Indians approximately 2,000 years ago. These figures are only fully comprehensible from the air. In fact, in 1937, before flight was commonplace, a highway was constructed through the Nazca lines, as no-one was yet aware of the lines' significance. It is unknown how the drawers achieved such geometrical precision in their art, or why they would draw figures that they could not view. (source)
The Dasht-e Lut Desert in central Iran, which is about 62,000 square miles in size, has never been inhabited by humans, and no traces of animal or plant life have been found in it. (source)
Over the past 5,000 years, the seemingly worthless Sinai Peninsula, mostly desert, has been the world's most besieged land, having been the battlefield for over 50 invading armies on their way between Africa and the Middle East.
Welwitschia mirabilis, found in the deserts of Namibia, can live for over 2,000 years, yet its central trunk is almost never more that three feet tall, with the largest one ever found being 4½ feet in height. Rather, its energy is transmitted into growing two huge leaves which never fall and continue growing throughout the plant's life. The leaves can be as long as 20 feet in length. (source)
In 2002, the Nevada state legislature authorized a license plate depicting a mushroom cloud from an exploding nuclear bomb. The picture would commemorate nuclear weapons tests conducted in the Nevada desert between 1945 and 1992. However, the Department of Motor Vehicles rejected the idea. (source)
The ancient Greeks constructed pyramids of porous rocks in desert climates, which were used as water catchers. They could capture and condense surprisingly large quantities of water. A group of 13 pyramids at Theodosia in the Crimea that were built around 500 B.C. averaged almost 40 feet high and were placed on hills around the city. As the wind moved through the stones, the changing temperatures throughout the day caused moisture to condense, run down, and feed a network of pipes. (source)
The tallest cactus in the wild can be found in the Sonoran Desert in Baja California in Mexico. It is a cardon cactus (Pachycereus pringlei) and measures 63 feet in height. It was found in April 1995. The tallest cactus raised by humans is a specimen of Peruvian apple cactus (Cereus uruguayanus) grown by Pandit S. Munji in Dharwad, Karnataka, India, which measured 70 feet in height in 2004. (source)
Jerusalem, after having been in Crusader hands for nearly 100 years, was lost shortly after a major victory by Saladin over the Crusader army at the Battle of the Horns of Hattin on July 4th, 1187. One of the main causes of the Crusaders' defeat is that the Crusader army set off from Acre towards the Sea of Galilee, through the desert without bringing adequate supplies of water. The horses became lethargic and collapsed, and the men undisciplined. Some surrendered to the Saracens in exchange for water. During the battle, the foot soldiers broke ranks, attempting to reach a well, where they were felled by Saracen arrows. (source)
The Nazca lines in Peru are not the only pre-Columbian drawings only visible from the sky to be found in North America. In the southeastern California desert near Blythe is a 167-foot-long figure of a man. Other figures were visible before World War II, until Blythe was used as a military training area and tanks and other vehicles obliterated many of them. Dating methods have dated the figures to around the year 900, give or take 100 years. Interestingly enough, one of the remaining figures appears to look like a horse, but the horse was not present in North America around that time. (source)