London is lucky at the moment to have encyclopedic shows of the flowering of American art in the last century, especially of New York artists influenced by Marcel Duchamp now at the Barbican.

WSJ: Review: Joining the Dots | 'Lichtenstein: A Retrospective' at London's Tate Modern

America has been both proud and defensive about the flowering of its art in the post-war years.

ECONOMIST: Roy Lichtenstein