Whats behind these mind-blowing Nasca Lines?

A tribe of people called the Nazca, or Nasca, once lived about 2,000 years ago in the coastal desert of southern Peru. Over time, they created dozens of giant designs on the floor of the Atacama desert.These ancient designs remained a secret until the 1930s, when airplanes started flying over South America. Then people finally noticed what are now called the Nazca Lines.

The Nazca designs are so big that you can only see them from the air.The image of a killer whale, for instance, is nearly as long as two football fields. Other huge animal designs include a spider, a monkey, and a hummingbird. There are geometric designs, too, including triangles and rectangles. Still others are perfectly straight lines that run for miles and miles. In all, the Nazca Lines cover 45 miles of the desert floor.
Nazca Lines

Many of the Nazca Lines were made by removing the dark surface rocks of the desert, leaving light-colored sand below. The lines look scratched in, like etchings. Sometimes piles of rocks form the lines. But why did the Nazca people make the Lines in the first place? Some experts think the Nazca used the Lines like a giant calendar, linked to the stars, sun, moon, and seasons. Others think the Lines were signals to aliens from outer space! Still others think the Nazca walked or danced along the Lines in special ceremonies. But only the Nazca themselves really know why they made such extraordinary designs.