Dr Catena lives in a basic brick compound attached to the back of the hospital with his wife Nasima, who is from Nuba, and their two adopted sons: Francis, seven, and Vincent, who is six months old.

Called “L’Exposition internationale des arts décoratifs,” it ran from April to October 1925, attracted 16 million people, and was a celebration of Modernism and Art Deco design. It occupied ...