In the Nazca Desert of Peru, south of the capital city of Lima, enormous networks of strange lines mark the stony surface of the land. Believed to be over two thousand years old, some lines run perfectly straight for miles. In contrast, other lines form complex designs and figures of animals. The scale of the designs is so huge, moreover, that from the ground no patterns are discernible. From observation towers nearly 50 feet high, the human eye can hardly notice the giant designs. They are startlingly clear from aircraft. One theory proposes the lines of Nazca marked airstrips for extraterrestrial spacecraft; logically, though, that theory ignores too many of the designs in the pattern to be widely accepted. Another theory suggests the figures are part of a huge astronomical calendar that might have been used to guide agricultural timetables. Still, another theory argues the patterns were a part of traditional rituals — ceremonies involving hallucinogenic plants and rites reflecting cycles of regeneration that might have incorporated the strange animal figures and patterns seen in the lines. Scientists and archaeologists continue studying these strange networks of lines; thus, they hope to solve the mystery of the origins of the lines of Nazca.