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After the las Ice Age ends, farming develops in Syria and Iran. By about 6000 ice, farmers are growing wheat and barley in the Fertile Crescent (Western Asia, the Nile Delta, and the Nile Valley
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Dogs become farmer's friends-from cheery companions to fearsome guardians. There is evidence to suggest that the first dogs are tamed wolves.
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Metalworking begins In Western Asia, where the world's first farmers live. Early farmers find naturally occurring Cooper nuggets and hammer them into beads. Soon after, they make objects from gold, silver, and lead
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Early farmers establish villages with basic buildings and shared structures. The first of these are found in Mesopotamia and in West Asia. Gradually, they expand to become small towns with organized communities.
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Cows and pigs are tamed. They provide a variety of materials aside from their meat and milk. When slaughtered, leather is made from their skins Their droppings enrich the soil. Pigs eat scraps to recycle them.
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Communities begin to surround their settlements with protective walls. In the town of Jericho in Palestine, a huge stone wall is constructed for defense, surveillance, and flood protection, keeping the 3000 inhabitants safe.
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Sheep and goats are raised for milk and food. Their caretakers move around with these flocks, looking for grass for the animals to nibble. People will begin weaving sheep wool into fabric around 4000 bce
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In Mesopotamia (modern-day Iraq), farmers build levees to hold back floods from their fields and channel floodwater into the crops they grow. Managing water in this way is called irrigation.
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Rice, which may have originated in India, is farmed throughout much of Asia. It grows in paddies, or fields submerged in water. Eventually, half of the world's population will eat rice as a staple food.
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The people of Western Asia discover how to extract copper from copper-rich rocks by heating them in fire (this is called smelting). They pour the molten copper into molds to make tools. Most people still use stone tools, so this period is called the Copper-Stone Age.
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In Varna, in what is now Bulgaria, people are buried with thousands of items of gold jewelry. The oldest gold treasure in the world, it will lie hidden underground for over 6000 years before being discovered by accident in 1972
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The first great cities develop in Mesopotamia. These are each ruled by a king. Grand brick structures called ziggurats are built, containing shrines, staircases, and towers.
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The first wheels are potter's wheels. They begin to appear in different cultures across the globe in around 3500 bce. Made of hardened clay, the wheel allows people to create better bowls and jars.
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The earliest wheels used for transportation are seen on Mesopotamian chariots and carts. They are built from solid wood and allow people to travel more easily than ever before.
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In Western Asia and Central Europe, the use of bronze becomes widespread. Bronze is made by melting copper with a small amount of tin. This results in a much harder metal. A trade in tin, which is a rare metal, also develops
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Mesopotamia's cities become important trading centers, using rivers to transport goods. Long-distance trade takes place between cities in Mesopotamia and in the Indus Valley in Pakistan. Luxury items such as spices, textiles, metals, and precious stones are exchanged.
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The first sewer systems are constructed by the Indus Valley civilization. Underground tunnels carry water from place to place, allowing most homes to have a bath, toilet, and water supply.
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Iron is first made by the Hittities of Western Asia, who use it to make weapons. Altought iron is the most common metal, it requires great heat to extract from rock. Instead of being poured into molds, it is softened and beaten into shape.
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The ancient Egyptians realize that wheels can be made lighter by cutting chunks from them. These spoked wheels allow the Egyptians to outrun their enemies in battle and trade goods more quickly
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The Sanxingdui people of China make large bronze statue with masklike faces. Their bronze includes lead, as well as tin and copper, making a stronger, heavier metal. The biggest statue, of a tree, stands almost 13 ft (4 m) high.
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The use of iron spreads from Western Asia to Europe, and India's Iron Age takes off at around the same time. Iron's hardness makes it ideal for tools, cooking pots, and nails, as well as weapons.
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In acient Greece, cities establish themselves as independent states with their own political systems. Athens, Sparta, and Thebes are some of the most important city-states.
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Iron working spreads throughout Europe, where readily available iron weapons lead to an increase in warfare. This 6th-century ace Greek vase shows blacksmiths using a forge (a powerful fire) to soften iron before shaping it with a hammer.
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In Peru and Bolivia, people begin large-scale smelting of copper. They use gold, silver an tumbaga (gold mixed with copper or silver) to make beautiful works of art in various colors.
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The Iron Age reaches sub-Saharan Africa, where the Nok people of Nigeria use iron to make spearheads, knives, and bracelets. The use of iron tools helps farming spread across Africa.
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Indian metalworkers make the highest quality steel in the ancient world. It is later exported to China and the West, where it is called "wootz". It is used to make exceptionally sharp, hard-wearing sword.
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In China, people discover how to make iron in a blast furnace-a furnace powered by a blast of hot air. The resulting iron can be remelted and poured into molds to make cast iron. Blast furnaces will not be invented in the West for almost 2000 years.
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Breaking soil up in preparation for sowing seeds is a tough job. Ancient people use sharp objects attached to sticks until the Han Dynasty Chinese people invent a durable iron plow that is easy to use.
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Rome becomes the first city to reach a population of 1 million people. Most Romans live in blocks of flats called insulae that are 6 or 7 stories high, maximizing space in the city.
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In the Byzantine Empire, around the Mediterranean, public areas and main roads in cities start to become closed off by shops. These eventually evolve into bazaars-covered markets where locals barter to get the best price for goods.
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Crops are grown in open fields in Western Europe. Farmers rotate crops between three plots: one for human food, one for livestock feeding, and one left fallow to recover nutrients that farming takes from the soil
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King Philip II of France orders a new wall to be built around Paris, stretching beyond the outskirts of the city. It is 8 ft (2m) wide with around 70 towers. Many other medieval European cities also rebuild their original walls to contain their growing centers.
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The first European blast furnaces begin operating in Germany, Switzerland, and Sweden. They use water wheels to power bellows that blow air into the furnace, and because of this, are built by rivers.
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As Europeans explore more of the world, crops are exchanged across the globe. Coffee, tea, sugar, and citrus fruits come from Asia; wheat, barley, and rye come from Europe; while tomatoes, corn, beans, potatoes, and Chile peppers move from the Americas. Animals are exchanged, too.
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During the Industrial Revolution, people move to work in factories. New towns grow rapidly around the factories to house workers.
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US-born inventor Eli Whitney invents a machine that makes removing seeds from cotton much easier and faster. By the middle of the 19th century, the material will become America's biggest export.
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The first public street lighting that uses gas is demostrated in London. This becomes the norm across towns and cities, solving the problem of limited light at night.
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Harvesting is slow and back-breaking work, done by hand with a scythe. Cyrus McCormick patents the reaper, a machine that aids in crop harvesting. His reaper cuts, threshes, and bundles grain as horses pull it along.
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Blacksmith John Deere invents a steel plow to keep the sticky soil of the American prairie from clogging up cast-iron plows. His invention is wildly successful.
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The world's first underground railway system opens in London. Moving transportation underground saves space and provides a quicker way to get around the busting city.
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Austrian friar and scientist Gregor Mendel conducts experiments with flowers and pea plants. Mendel describes how certain traits, such as color or size, are passed on through the generations. This knowledge is used by farmers to selectively breed crops.
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Australian Hugh Victor Mckay produces the first commercially successful combine harvester a machine that cuts, threshes, and cleans crops with one pass of its mighty rotating blades.
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The first high-rise building, nicknamed a "skyscraper", is built in Chicago, IL. Building upward saves space in the packed city center and is possible due to the invention of the elevator and sturdy steel.
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Steam-powered threshers that separate grain from cereal crops are expensive and hard to move. American inventor John Froelich invents a rudimentary tractor that can pull the thresher with ease.
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Farmers in Mexico lead a movement to update farming practices and produce more nourishing food. the technologies spread across the globe.
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Genetically modified (GM) crops become common. They can increase yield, boost nutrition, and resist pests, but potential food safety risks from "tampering" with the natural ecosystem are a worry for many.
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Half of the world's population now lives in cities. Megacities, which have populations of more than 10 millions, have become more common. Tokyo, Japan, is the biggest city in the world, with around 13 million people living there.