Portrait of a City: US Urban Photography at Dulwich Gallery

Dulwich Picture Gallery in London is showing Portrait of a City, only the second photography exhibition in the gallery's history. It pulls together 20th-century American urban work from Alfred Stieglitz, Edward Steichen, Saul Leiter, Dorothea Lange and Lewis Hine, running from pictorialist New York through to social documentary classics including Lange's Migrant Mother and Hine's Empire State Building ironworker portrait.