问答题 If you fly over the Nazca Desert along the southern coast of Peru, you will see huge drawings in the sand; a monkey, a spider, flowers, triangles, rectangles, zigzags, spirals, even human forms with crowned heads. Also, straight lines can be seen spreading out from a circle, like spokes in a wheel. Some drawings are more than six hundred feet from end to end, longer than two football fields. Some continue for miles, up hills and down valleys. In all, the markings cover 250 square miles of desert. Some drawings are so large that you can tell what they are only by looking at them from the air. But no one knows how they got there, or why. We do know they were made about two thousand years ago by South American Indians called the Nazcas. The Nazca people lived in a green valley just below a huge stretch of desert called the pampas, meaning "flat place". The air around the pampas is hot and dry, and the pampas gets only about half an inch of rain each year. So the markings made long ago on its sandy, stony surface have not been worn away by the weather even after two thousand years. To find some clues about why the drawings were made, we can turn to history and anthropology. We know that Spain conquered Peru in 1532. The Spaniards destroyed much of the Peruvian way of life, except in remote regions of the Andes Mountains. Today, descendants of the Peruvian natives who survived live in villages along the mountainsides. Farmers there have to hike thousands of feet each day to reach their fields. On their way, many of them perform religious ceremonies. Those ceremonies offer clues to the meaning of the Nazca lines.