A black and white photograph from 1958 shows Marcel Duchamp and Salvador Dalí on a hot August day in Cadaqués, on the east coast of Spain. The artists are trekking uphill with their wives, Alexina (‘Teeny’) Duchamp and Gala. Duchamp is in shorts and a straw hat; Dalí is dressed like a toreador in a white suit, clutching a gnarled staff. The image says something about their different styles – Duchamp’s cool asceticism, Dalí’s camp showmanship. They make an odd couple. But as the Royal Academy’s exhibition Dalí/Duchamp (until 3 January) makes clear, their lives and interests ran in close parallel from their first meeting, around 1930.