Here's a representative quote
As Tijuana has expanded into the hilly terrain to the east, squatters have fashioned an elaborate system of retaining walls out of used tires packed with earth. The houses jostling on the incline are constructed out of concrete blocks, sheets of corrugated metal, used garage doors and discarded packing crates — much of it brought down by local contractors and wholesalers from across the border.
Once such a settlement is completed, it is protected from demolition under Mexican law — and the government is eventually obliged to provide plumbing, electricity and roads to serve it. In Mr. Cruz's view, the process is in some ways a far more flexible and democratic form of urban development than is the norm elsewhere.