If Mexico City is a book, then it's one that's constantly being rewritten. For the photographer Brian Rosa the city is in a constant state of flux and reinvention-never completely finished; never completely reinvented. He began photographing the place while living there on a research fellowship focusing on the large scale planning that occurred in Mexico City leading up to the national Centennial Celebration of 1910. Seeing a discrepancy between "the rigid central planning of [that era] and the current chaos of informal settlements and economies," Rosa says that he "ended up trying to reconcile these two conflicting histories, which have both manifested themselves heavily on the built environment."The resulting series, "Palimpsesto Urbano: Mexico City," is not intended to be a comprehensive visual catalog of the city; rather, it calls attention to the city's constant state of evolution-pairing the permanent with the transitory. "I can only say that Mexico City is a place of contrasts-be they aesthetic, socioeconomic, or otherwise," says Rosa. "I expected these incongruities, but for them to be more spatially separate. To live in Mexico City is to cross countless invisible borders every day; to be constantly barraged with all things-beautiful and ugly, banal, and remarkable-that this world has to offer."Colonia Santa FeEcatepec de MorelosColonia CuauhtémocEcatepec de MorelosCiudad NezahualcóyotlColonia PolancoColonia IxtacacloColonia TacubayaColonia Sante FeColonia Santa FeColonia CoyoacanThis work is currently being exhibited at Centro Cultural BORDER, and was supported by The Stein Institute for Urban and Landscape Studies at Cornell University and El Taller Internacional de Arquitectura, Urbanismo, y + in Mexico City. If you're interested in learning about the redevelopment of Mexico City's historic center, you can read Rosa's article in the current issue of The Next American City.