The site of Tempelhof Airport in Berlin was once a field for military demonstrations. It was turned into an airport in 1923, and came to be known as the hub of Berlin Airlift. After W.W. II, its main building was one of the world’s 20 largest. Tempelhof ceased operation in 2008, but is now poised for repurposing as the venue for “Diversity United,” an exhibition presenting 90 European artists—including Olafur Eliasson, Alicia Kwade, Erwin Wurm, and Wolfgang Tillmans—in two hangars. The show is backed by three presidents, one of which is Russia’s Vladimir Putin (the others are Germany’s Frank-Walter Steinmeier and France’s Emmanuel Macron). The art addresses the subjects of freedom, dignity, and respect, conflict, dialogue, and identity. —E.C.