Some of the Nazca Lines, mysterious geoglyphs that span a vast swath of the rugged Peruvian desert, may have once been a labyrinth with a spiritual purpose, a new study suggests.

MSN: Peru's mysterious Nazca Lines form a labyrinth, says study

But just why ancient people created the Nazca Lines has been an enduring mystery: Some archaeologists have suggested it was an alien landing strip, a primitive sun calendar, or an irrigation system.

MSN: Peru's mysterious Nazca Lines form a labyrinth, says study

Maria Reiche, a German mathematician, spent more than half a century investigating and protecting 16 mysterious ancient drawings known as the Nazca Lines over a 60 kilometre (45 mile) area in the Peruvian desert.

BBC: News | Americas | Lady of the lines

At the time the Nazca Lines, which span 85 square miles (220 square kilometers), were drawn, "people were not looking at this stuff from the air, they were looking at stuff from the ground level, " said Timothy Ingold, a cultural anthropologist at the University of Aberdeen, who was not involved in the study.

MSN: Peru's mysterious Nazca Lines form a labyrinth, says study