1) Famed as the birthplace of Mohammed, the founder of Islam, the city of Mecca was the holiest city in the Moslem world since the seventh century. 2) Once known as Macoraba, it is located in the western part of what is now Saudi Arabia. 3) The Haram, or great mosque, sit in the centre of the city, and it contain a small sanctuary, which the faithful considers the most sacred place in the world. 4) To this sanctuary, known as the Kaaba, comes pilgrims from all over the Islamic world. 5) Indeed, Mecca's economy was almost totally dependent on these visitors.

1) The Toltec civilization flourished in what is now Mexico from about 900 AD to 1200 AD. 2) Building their capital at Tula, north of present-day Mexico City, the Toltec create a vast empire. 3) They conquer the ancient Maya, who have once occupied the Yucatán Peninsula and parts of Guatemala. 4) However, the Toltec state is not long-lived. 5) Tula was left in ruins by a disastrous civil war, and Toltec civilization was caused to decline. 6) The power vacuum that this development created was eventually filled by the Aztecs, who cross into Mexico in about 1300. 7) The Aztecs created their own empire on the ruins of the Toltec civilization and absorb much of the Toltec culture. 8) Deciding to establish their capital in Mexico City, the Aztecs created another great civilization. 9) They ruled the region for more than 200 years when they were conquered by the Spaniards.

1) The Greek philosopher Aristotle, who live during the fourth century BC, teached that all matter could be perfected, thereby giving rise to the pseudoscience of alchemy, the attempt to "perfect" base metals by turning them into gold. 2) Alchemists clinged to the idea that they might also discover the elixir of life, a substance that could extend human life. 3) Although it reached its height during the Middle Ages, alchemy had began in the Greek city of Alexandria, Egypt, in ancient times. 4) There is evidence that it is also being practiced in China at the same time. 5) Greek and Roman philosophers, including Empedocles (fifth century BC) and the Roman emperor Caligula (first century AD) studied alchemy and, in the process, discovered a number of principles that will eventually lead to the rise of chemistry many centuries later. 6) In the third century, for example, the Greek Zosimus experiments with sulphuric acid and discovers many of its properties and capabilities. 7) For four centuries, Arab alchemists experimenting with metals such as gold, arsenic, and sulphur uncover a number of important chemical principles and techniques, which they recorded and published. 8) This knowledge has came to Europe through Spain, which the Arabs controlled for many centuries. 9) European thinkers such as Roger Bacon, Thomas Aquinas, and Albertus Magnus helped furthering the study of what has became known as chemistry. 10) In the 16th century, the Swiss philosopher Paracelsus theorizes that there is one element from which all others springed and that it can act as the universal solvent, as a cure for all diseases, and as the philosopher's stone (the substance that will turn base metals into gold). 11) The followers of Paracelsus took two directions: the first developed into legitimate scientists, leading the way to France's Antoine Lavoisier, the founder of modern chemistry. 12) The second group eventually turned alchemy into the study of black magic and sorcery, giving it the image it had retained to this day.

1) Members of a group of people speaking the Nguni languages, the Zulu live in what is now South Africa. 2) With the largest number of that country's indigenous people, the Zulu ethnic group numbers about nine million. 3) In the 19th century, they united with other members of the Nguni under a Zulu leader named Shaka, who rule from 1816 to 1828. 4) Shaka extends Zulu control beyond their native lands into the area known as Natal on the Indian Ocean. 5) In 1879, war broke out between the Zulus and the British, who had colonize southern Africa. 6) The Zulu were victorious in several early battles. 7) If the British did not change their tactics and brought up reinforcements, the Zulu would surely vanquish them. 8) However, the Zulu were eventually defeated, and their country was divided into 13 separate kingdoms under British control. 9) In 1887, Zululand was officially name a crown colony of Great Britain. 10) Under apartheid, parts of Zululand have been combined into Kwazulu, a separate black homeland. 11) Apartheid was a political system designed on keeping power and wealth in the hands of whites and on denying civil and economic rights to nonwhite South Africans. 12) At the heart of the system was the enforcement of a strict policy of racial segregation. 13) With the abolition of apartheid in 1994, Kwazulu was joined with Natal to form a new province.

1) A native of Vienna, Austria, Christian Doppler (1803–53) had been a physicist who developed a theory about light waves that drawed upon what was already knew about the movement of sound. 2) Knowed as the Doppler effect, it was first published in a study entitled "Concerning the Coloured Light of Double Stars" (1842). 3) As we move toward a blaring horn, Doppler explains, the sound gets louder and louder; as we move away from the horn, the sound diminishes. 4) This, he argued, can being compared to the way in which light from a star reaches us. 5) As the earth moves closer and closer to the star, its light arrives in shorter and shorter wavelengths (toward the violet end of the spectrum); as the earth moves farther and farther away from the star, its light has arrived in longer and longer wavelengths (toward the red end of the spectrum). 6) Today, Doppler's work had importance in research on the nature of the universe and is especially important to understanding the movement of the stars.