Elite auction house Sotheby's on Friday adopted a poison-pill defense strategy to fend off a challenge by investor Dan Loeb's hedge fund Third Point.

Sotheby's announced a plan to expand its share base in a rights issue that aimed to weaken Loeb's push to force out the company's chairman and chief executive William Ruprecht, and take a seat on the board for himself.

Malala Yousafzai, the Pakistani girl shot by the Taliban for campaigning for girls' schooling, added another award to a growing list on Friday.

She was given the RAW in WAR Anna Politkovskaya Award, named after the Russian investigative journalist who was shot dead seven years ago next Monday.

An Italian weekly said in its Friday edition that a new painting by Leonardo da Vinci of Renaissance noblewoman Isabella d'Este has been reliably authenticated with carbon dating.

The portrait, which was believed to have been either lost or never even painted, belongs to an Italian family which kept it in the vault of a Swiss bank, the Sette magazine reported.

A Chinese investment firm on Thursday announced plans to resurrect London's Crystal Palace, once the largest glass structure in the world.

The planned £500 million ($800 million, 600 million euro) re-creation by the ZhongRong Group is on the same size and scale as Joseph Paxton's original cast iron and plate glass masterpiece.

Swedish inventor and scholar Alfred Nobel (1833-1896), who made a vast fortune from his invention of dynamite in 1866, ordered the creation of the Nobel prizes in his will.

His 1895 testament stipulated his fortune was to be placed in a fund destined to honour "those who, during the preceding year, shall have conferred the greatest benefit on mankind".

World-famous, reclusive artist Banksy is loose on the streets of New York, hosting a unique show that has whipped up excitement among hipsters and the chattering classes.

The England-based graffiti maestro, who has never been formally identified, has promised to unveil a new piece of art on each day of the month somewhere in the city.

With the magical sound of wooden flutes, the scent of incense, and the warm Andean sun making shadow patterns across the rolling hills, this event has all the hallmarks of a happy, festive occasion. Families spread out picnics; strolling musicians and vendors sell cotton candy, toys, flowers and food.

But this celebration is taking place in a cemetery, el Cemeterio de Nueva Esperanza, one of the largest cemeteries in the world. And the event is the Day of the Dead, celebrated throughout Latin America on Nov. 1, a day after American kids go trick-or-treating for Halloween.

A model of Pablo Picasso's famed Chicago sculpture will be auctioned next month and Christie's estimates it will sell for between $25 million and $35 million.

The late Spanish artist created the piece, named "Tete," between 1962 and 1964. The iron and sheet metal model that goes to auction on Nov. 4 in New York is 41 ½ inches (11 centimeters) tall and 27 ½ inches (0.69 meters) wide. It was later made into the 65-foot (20-meter)-tall, welded-iron sculpture unveiled on Aug. 15, 1967 in Chicago's downtown Daley Plaza.

Activist shareholder Dan Loeb Wednesday launched an all-out attack on the management of art auctioneers Sotheby's, calling for a new chief executive and criticizing company expenses.

Loeb, chief executive of hedge fund Third Point, released a blistering letter to Sotheby's chief executive William Ruprecht in which he said the auction house, which traces its history to 1744, had fallen behind rival Christie's in key emerging markets, Internet sales and the growing modern art segment.

A portrait of Nelson Mandela by British artist Richard Stone and a portrayal of him playing the role of Jesus at the Last Supper are some of the works on display in London's "We Love Mandela" exhibition.

Some 22 artists, all South African with the exception of Stone, are displaying around 50 works reflecting the "emotions of people", their feelings and ideas about South Africa's first black president, exhibition curator Natalie Knight told Agence France Presse.