In Geneva, Christie's auction house is selling hundreds of jewels that belonged to Austrian billionaire Heidi Horten, whose German businessman husband made his fortune under the Nazis. With a pre-sale estimate of 150 to 200 million dollars, Christie’s International Head of Jewellery Rahul Kadakia says the auction is on a level not seen since the 2011 sale of Elizabeth Taylor's collection. Some Jewish groups have called on Christie's to stop the sale. David de Jong, author of the book 'Nazi Billionaires', says the "lack of historical transparency" from the auction house is a problem. "He was an opportunist for the most part, who became a member of the Nazi party as well" notes David de Jong, author of 'Nazi Billionaires'. Christie's says that "all of the proceeds are going towards charities" and that it will also make a "significant donation towards Holocaust research and education." IMAGES AND SOUNDBITES