U.S., Aug. 24 -- Mykonos is the party isle of Greece. It is a playground for the rich and famous, but it is not likely the Arabs, jetsetters, Russian tycoons, and large tour operators know that this pleasure playground is built on the sweat and suffering of its workers.

After hundreds of young employees serve island visitors, turning over millions of euro in just one evening, they return to their favelas - shipping containers and shacks that they call "home." These half-hazard structures are painstakingly hidden to make them invisible to tourists.

Said a former employee of a beach bar restaurant in Mykonos who worked a 14-hour shift from 11 am to 1 pm, it was the most tragic experience of his life. Despite his need to earn money, he event...