The top prize at the Cannes Film Festival in France, the Palme d'Or, has been won by The Tree of Life, directed by Terrence Malick. The best actress award went to Kirsten Dunst for her performance in Lars von Trier's film Melancholia. Von Trier was

thrown out

of the festival last week for joking that he was a Nazi. Kirsten Dunst briefly alluded to the row in her

acceptance

speech.

"Thank you so much to the jury. This is an honour that is a once-in-a-lifetime thing for an actress. And thank you to the Cannes Film Festival for allowing our film to still be in competition. And I want to thank Lars for giving me the opportunity to be so brave in this film and so free."

A new study suggests the Inca civilisation in the Peruvian Andes may have

owed part of its success to

llama droppings. Research by the French Institute of Andean Studies suggests the Incas

flourish

ed after they began using llama dung for fertilizer. James Read reports.

In the 15th century, the Incas ruled the biggest empire South America had ever seen, but their

fabulous

cities of gold had humble origins. Research conducted in the Inca heartland in Peru suggests their civilisation emerged partly as the result of an extraordinary agricultural development nearly 3,000 years ago. Samples of mud and pollen taken from a lake suggest llama dung, used as fertilizer, helped the ancient people of the Andes make the transition from hunter-gathering to farming. Centuries later, it allowed the Incas to farm maize in the high mountains, providing a grain