At the end of the work day, when construction workers return to their campsite, a corrugated metal gate, marked simply with a "Camp 2" sign and list of safety regulations, represents a passage between two worlds. Luxury high-rise condominiums lining the street loom overhead. Down below, inside the gates, are the makeshift homes of the families of the workers who build the expensive condos, shopping malls and glitzy restaurants popular with Bangkok’s expatriates and wealthy Thais. The contrast in the daily lives of families living just a few hundred meters away from each other could not be starker.