Esteemed American photographer Helen Levitt lived in Mexico City in 1941 and photographed the city's rapid urbanization and traditional ways of life, then struggling to coexist.Levitt's astute vision captured a city and its inhabitants on the cusp of modernity, with neither sentimentalism nor romanticism. Working almost exclusively in urban and semi-urban areas of Mexico City, she confronted directly the conflicts and juxtapositions that provided inescapable evidence of Mexico's presence in the modern world, and she did so with compelling force and dry wit. These images show street scenes in Chapultepec Park and other distinctly urban zones, as well as the working-class neighborhoods then on the periphery of the city. Over half a century later, her photographs unlock the past, helping to decipher the sprawling city of today. Most of these images have never before been exhibited or published.