August 2, 1990 through February 28, 1991
The period of <span>Muhammad in Medina</span><span> started with the </span>Hijra<span> (migration to Medina) in 622 and ended with the </span>conquest of Mecca in December 629. <span>Muhammad instructed his followers to emigrate to Medina until virtually all of his followers had left </span>Mecca<span>. Being alarmed at the departure of Muslims, according to the tradition, the Meccans plotted to assassinate him. he fooled the Meccans who were watching him, and secretly slipped away from the town.</span>
(make sure to thank me)
The treaty of Versailles and the economic consequences of its terms were a significant concern and added to Germany's humiliation. It also forced Germany to pay a huge sum in reparations, which it couldn't afford setting it back behind every other nation during that time.
According to the writings of Vitruvius, the Greek mathematician Archimedes created a primitive elevator in 236 B.C. that was operated by hoisting ropes wound around a drum and rotated by manpower applied to a capstan. In ancient Rome, a subterranean complex of rooms, animal pens and tunnels stood beneath the Colosseum. At various intervals, elevators powered by hundreds of men using winches and counterweights brought gladiators and large animals up through vertical shafts into the arena for battle.
In 1743, Louis XV had what was referred to as a “flying chair” built to allow one of his mistresses to access her quarters on the third floor of the Palace of Versailles. Similarly, a “flying table” in his retreat château de Choisy allowed the king and his private guests to dine without intrusion from the servants. At the sound of a bell, a table would rise from the kitchen below into the dining room with an elaborate meal, including all of the necessary accoutrements.
By the mid-19th century, elevators powered by steam or water were available for sale, but the ropes they relied upon could be worn out or destroyed and were not, therefore, generally trusted for passenger travel. However, in 1852, Elisha Graves Otis invented a safety break that revolutionized the vertical transport industry. In the event that an elevator’s hoisting rope broke, a spring would operate pawls on the car, forcing them into position with racks at the sides of the shaft and suspending the car in place. Installed in a five-story department store in New York City in 1857, Otis’ first commercial passenger elevator soon changed the world’s skyline, making skyscrapers a practical reality and turning the most valuable real estate on its head—from the first floor to the penthouse.
The post war economic boom was due primarily to foreign debt. The United States made substantial loans to European countries during World War I. Although the Europeans had very little money to repay the debts, American bankers restructured the loans to facilitate repayment. Although a brief recession occured in the early part of the decade, the Roaring Twenties saw the expansion of the stock market and considerable profit for investors.