The Nazca Lines are mysterious images stretching across the Nazca Plains in Peru. They are an enigma, intriguing archaeologists and alike as to their origin and purpose. No one has any proof as to who built them or why. They are thought by many to have been created between 200BC and 600AD, by the Nazca civilization, and used for rituals relating to astronomy.
Intriguingly however, they are only really observed as the images they portray from above.