Some 2,500 years ago, Nazca was the seat of a highly advanced pre-Inca civilization that created what many have called one of the most baffling enigmas of archeology: Enormous geoglyph figures of animals, birds and geometric patterns and spirals etched in the desert.

Since they were first discovered in the 1920s, the Nazca Lines have puzzled scientists and attracted mystics and UFO enthusiasts. The figures — among them a hummingbird, monkey, heron, whale, cat with fish's tail, spider and flower — measure up to 900 feet (275m) long and can only be seen clearly from the air.

Each year, about 80,000 tourists fly over the pictographs.

The drawings cover a 35-mile (56km) stretch of high desert plain 250 miles (400km) south of Lima, and the theories of their origin are as varied as they are imaginative. According to one, they were a landing strip for flying saucers, made by or for extraterrestrials.

Maria Reiche, a German-born mathematician who spent more than half a century studying and protecting the 180-square mile (450sq km) protected zone, concluded they represent a giant calendar keyed to the movements of the sun, moon and constellations, which told ancient desert dwellers when to plant and irrigate their crops.

Reiche opened a small museum in 1994, where one of her old friends and associates, Victoria Nikitzhi, still gives lectures using a scale model of the lines.