It’s amazing how cities separated by language, culture and continents can have so much in common. I thought about this while reading Manuel Vigo’s blog post about his hometown of Lima. The Peruvian capital of his youth “was a quiet city, its downtown a dodgy and dirty place,” he writes. “I remember that as a child during those years, the city seemed isolated from the rest of the world.”

Today, Lima’s sidewalks bustle with pedestrians, and its streets (for better or worse) are clogged with cars. To a certain extent, this is par for the course in the urban developing world. And the globalized economy, which has helped make Lima one of Latin America’s fastest growing cities, has certainly made it a busier place. But another factor is Lima’s embrace of its informal settlements. For decades, slums have proliferated on the city’s fringes, and many of them spent years isolated from Lima proper. But the city has gradually integrated these poorer neighborhoods into its urban fabric, connecting them to the water and electrical grids, providing them with transportation, and distributing property titles to informal settlers, giving them not just a better standard of living, but a stronger stake in the city in which they live.

In certain respects, it’s the reverse of what we see happening in many U.S. cities today. No, urban America doesn’t have informal settlements like the ones in Peru. But it’s not at all rare to find neighborhoods in the U.S. that are being systematically disconnected from their city. In Detroit, bus service has become so unreliable as to turn sections of that city into isolated islands. Hospital closings in Queens, N.Y. have made public medical care scarce in many neighborhoods. Camden, N.J. has effectively withdrawn its police force street by street.

In bits and pieces, these neighborhoods are becoming dislocated from the urban core. They may have water and lights, but it’s impossible to deny that their formal city services are shrinking. As Lima is reaches out toward its poorest neighborhoods, budget cuts are forcing cities like Camden and Detroit to abandon theirs. The reversal of roles is striking.