A landscape by one of Switzerland's best-known artists, which has been out of the public eye for more than 50 years, will be auctioned next month.The oil depicting the Dents-Du-Midi mountain range in bluish hues was unveiled overnight in the Alpine resort of Champery in the Valais canton (state), where Ferdinand Hodler painted it during a prolific summer holiday in 1916."He sold it the next year to a Swiss collector. It was only shown twice in exhibits in 1938 and in 1950 and has never before been photographed," Matthias Oberli, of the Swiss Institute for Art Research, told a news conference."This painting is practically unknown. It is a real find," he said. Mr Oberli, who is compiling a complete catalogue of Hodler's works, said 70 other works had disappeared and may also resurface if their owners recognise their value.Sotheby's predicts the Dents-Du-Midi scene will fetch 5 to 7 million Swiss francs ($4.7 to $6.7 million) - the highest pre-sale estimate for a Hodler painting.It goes under the hammer on November 27 in Zurich.The auction house declined to identify the owner, but said the work has been in the same family since 1917.Lake Geneva as seen from Saint-Prex fetched nearly 11 million Swiss francs in June, doubling its pre-sale estimate.The Swiss artist, who lived from 1853 to 1918, was deeply attached to nature and had a style that was part Realist, part Symbolist and part Expressionist. "Hodler didn't just paint Alpine landscapes, he captured the essence of mountains," Urs Lanter, head of the Swiss art department at Sotheby's, told Reuters."In the last 10 years the Swiss market has grown greatly, with top works fetching prices three or four times higher than a decade ago."Swiss Justice Minister Christoph Blocher, whose far-right Swiss People's Party (SVP/UDC) is leading a controversial anti-immigrant campaign, is a collector of Hodler's works.The sale coincides with a Hodler exhibition opening at the Musee d'Orsay in Paris in mid-November.