September 1, 2006—It's a dirty job, literally. But Carlos Barrios, a former accountant in Mexico City, thinks he's the one to do it (map of Mexico).

As workers across the United States take a day of rest this Labor Day, Barrios will likely be swimming the Mexican capital's sewers. He'd be submerged in a toxic brew of garbage, bacteria, excrement, dead animals—even the occasional murder victim.

His job: to clear blockages and ensure these contaminated waters don't gush into city streets, subway tunnels, or people's homes.

Watch as his team responds to an emergency call, and try not to hold your breath as Barrios dives into the bowels of one of the most polluted cities on Earth.