The small, powerful tugboats that manoeuvre large, unwieldy freighters and liners in and out of their moorings were a vital feature of busy harbours and docks in the post-war years. In his assemblage, Cherbourg, 49 (on display nearby), Cohen recalls his first sight of Europe - when, looking out of the transatlantic liner's porthole, he spotted a French tug. Tugs continued to feature in his vision of Europe's coasts and rivers for the next 50 years. He also re-used the composition in one of his rare lithographs, the poster for his solo exhibition in Paris in 1958.