US-American violist David Aaron Carpenter holds the Macdonald viola by Antonio Stradivari, made in 1719, at Sotheby's gallery in New York, March 27, 2014. A rare Stradivari viola, considered to be one of the finest in existence, is expected to fetch more than $45 million in a sealed bids sale this spring, which would set a world record for the most expensive musical instrument ever sold. The 'MacDonald' Viola, made by the famed Italian artisan Antonio Stradivari in 1719, is the first to be on the market in 50 years, according to Sotheby's auction house. REUTERS/Eduardo Munoz (UNITED STATES - Tags: SOCIETY)