How did the Incas build their roads? The Incas built an extensive road network by using a labor tax, but they used different construction techniques depending on the landscape they were building through. We have a lot of roads today. It is estimated that there are 200 million km of roads around the word at […]
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How many of Nostradamus’s predictions have come true? The number of Nostradamus’s predictions that have come true depends very heavily on how you want to look at it. If you are asking how many have come true, then the answer is 0. If you are asking how many can be made to sound as though
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Why was the Waldorf-Astoria hotel built because of a feud? The Waldorf-Astoria hotel was built because of a dispute over who should be able to use the name “Mrs. Astor”. The original Waldorf-Astoria hotel doesn’t exist anymore. It was knocked down in 1929 and the land was sold to the Empire State Inc, a group
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How did the Phoenicians dominate the sea for a thousand years? The Phoenicians were able to dominate the sea for nearly a thousand years because of the ship technology they had, because of the way they controlled their colonies, and because of the collapse of other civilizations during the Bronze Age.. The Phoenician Empire wasn’t
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How does a 3D movie work? A 3D movie works by having two very slightly different versions of the movie that are filmed a tiny distance apart. We, like most predators, have our eyes at the front of our faces, pointing forwards. Most prey animals have their eyes at the side of the head. The
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How does an earthquake early warning system work? An earthquake early warning system works by detecting the P wave that comes from the earthquake’s epicenter. Earthquakes are caused when tectonic plates jam against each other and then suddenly move. There are three types of tectonic plate boundaries. There are divergent boundaries. These are where two
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How do people breathe on a submarine? Submarines can carry a pressurized air supply, but most modern submarines make oxygen through a process called electrolysis. Producing enough oxygen for all of the people on a submarine isn’t the only thing to consider when trying to keep them alive. The air we breathe is 78 percent
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How do people live in the Arctic and the Antarctic? People live in the Arctic by staying warm, protecting themselves from the extreme weather, and having enough food to last through the winter. (In case you get confused, the Arctic is where the North Pole is located and the Antarctic is where the South Pole
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What was the Great Fire of Rome? The Great Fire of Rome was a huge fire that decimated the city of Rome in 64 AD. It is the fire that burned Rome while Emperor Nero was supposed to have been playing his fiddle. Most major cities that have a long history will have had a
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How does hydroelectric power work? Hydroelectric power works by converting the gravitational potential energy of stored water into kinetic energy, and then into electricity. As the first law of thermodynamics says, energy cannot be created or destroyed, only transformed from one type into another. This is what hydroelectric power does. A hydroelectric power station takes
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