Claude Monet’s 'Marée basse aux Petites-Dalles; from 1884 is from the collection of Mamdouha and Elmer Bobst. It is a key highlight of Sotheby’s Impressionist & Modern Art Evening sale on 9 May in New York. Works from the collection will be sold to benefit the causes the couple supported during their lifetimes including New York University, Memorial Sloan Kettering Cancer Center and Princeton University.