The mural has a long history in Mexico, with its most famous being created in the 1920s. Iztapalapa is on the outskirts of Mexico City, and it’s at the heart of a trend to create new murals. Initially, the murals in Iztapalapa were designed to produce streets where women felt safe walking alone; but they took on a life of their own. The Economist’s Mexico bureau chief Sarah Birke tells their story.