A、Disadvantages of tall buildings. B、The Crystal Palace Exhibition. C、Modem elevators. D、The invention of the elevator. D

Los Angeles today is the second largest city in America, sprawling over 464 square miles along the southern California coast. It is the center of the entertainment industry, end it has a balmy climate of mostly sunny days.
    But there was a time when Les Angeles was nothing more than a tiny Indian village. The Spanish expedition searching for Monterey Bay camped there the night of August 1,1769. Twelve years later, other Spaniards started a settlement at the village, which remained unchanged for decades. Yankee sea traders used the settlement as a port, and the California gold rush brought some new economic life to the village, but the town remained quite small. It was not until the completion of the transcontinental railroads in 1869, and the discovery of oil in the 1890s, that the population began to grow.
    Later, during the two world wars, Los Angeles experienced move growth, in part because of the new airplane industry. At about the same time, the arrival of two New York motion picture producers in search of sunny weather marked the beginning of an entertainment industry that has become a multibillion-dollar industry today. In just the past 100 years, this tiny sea village has grown into the sprawling metropolis that we know today.

I wonder how many of you would went to work in a tall building such as the Empire State Building if you had to climb 102 flights of stairs to reach the top. Not many, I imagine. If it were not for the invention of elevators, or lifts, tall buildings would be unusable.
    The first lift was just a box suspended on a rope. Using a series of pulleys, a group of oxen ox strong men would pull the rope end lift the box to a higher point. Lifts were used only for heavy materials, not passengers. Even in the nineteenth century, when steam power was used to operate the lifts, people didn’t ride them. They didn’t trust the rope that held the box.
    In 1853, Elisha G. Otis invented the first safe lift. He showed his invention in New York at the Crystal Palace Exhibition. At the exhibition, Otis was pulled up in an open box that was attached to two guide mils. When he was lifted far above the spectators, he gave the order to cat the rope. To the amazement of the crowd, the lift did not fall straight downward to the floor. Instead, it was held fast to the guide rails by a certain device. He had built powerful metal clamps on the carriage as a safety measure. The demonstration worked, and people have been riding as passengers in elevators ever since.