Etched into the earth on the Nazca Plains in Peru are giant symbols drawn perfectly straight. Some are hundreds of metres long. They look as if they were drawn by some giant hand two thousand years ago. And the strange thing is, they can only be seen from the air. So how did the ancient Nazcans draw them? Researchers say they could have created hot air balloon or kites to fly and view their work. Indeed, an experiment was carried out and it proved that the Nazcans could have made a working balloon. The symbols themselves are of animals and plants. Yet some are long strips of land without any direct meaning. A writer named Erich Von Daniken believed that these were landing strips for alien spacecraft, and that aliens could have drawn them. They may also be for contacting these aliens. Maria Reiche, an astronomer, says that these lines may be used as a calendar, or to keep track of the stars and planets. There is a monkey drawing that has a coiled tail that looks similar to the orbital lines of our solar system. There are even more obscure theories that suggest that there were giant people 2,000 years ago. Yet, they are still a mystery.