An auction in New York today is almost certain to make the celebrated artist a record-breaker. But, overshadowing what could be a $60m sale, are questions about works that have allegedly disappeared

An auction in New York today is almost certain to make the celebrated artist a record-breaker. But, overshadowing what could be a $60m sale, are questions about works that have…

A 1940 self-portrait by Frida Kahlo has sold for $54.7m and made auction history at Sotheby’s in New York.