What are the mysterious Nazca Lines?

Imagine standing in the middle of a desert in Peru, looking down at your feet. You see rocks, sand, maybe a lizard. Nothing special. But if you could suddenly fly straight up like a rocket—high, high into the sky—you'd gasp. Because drawn across the desert floor below you, bigger than football fields, are perfect pictures: a spider with curly legs, a hummingbird with an impossibly long beak, a monkey with a spiral tail. They're called the Nazca Lines, and they've been lying there for about 2,000 years, waiting to be discovered.
The Nazca people made them between roughly 500 BCE and 500 CE—that's before the Inca, before anyone in Peru had metal tools or wheels. They had string, wooden stakes, and an idea. The desert floor here is covered in dark reddish rocks. Underneath those rocks? Lighter-colored sand. So the Nazca didn't paint or carve. They just cleared away the top layer of rocks, revealing the pale ground beneath, and suddenly: lines.
