The principal exhibition space of the Southbank Centre, hidden on a back rampart of the vital nonprofit arts center, hosts terrific blockbuster shows, usually £11 to £20, which have included Ansel Adams, Roy Lichtenstein, 1920s Surrealism, and a 60-artist panorama of modern African art. It also takes itself quite seriously, which can be good for a laugh. It’s slated to be closed for renovation until late 2017.