The middle and upper classes live in suburbs, or in the central part of the bigger cities in apartments, where there is urban planning. Many of the houses they live in are like miniature fortresses, located behind walls embedded with metal spikes, barbed wire, broken glass, and sometimes all three. The gates to these houses are barred at night, the house is locked; guard dogs patrol the yard. These houses are often self-sufficient as well. The houses have backup generators, because the electrical grid in Haiti is unreliable. Some even have rooftop reservoirs for water, as the water supply is also unreliable.