LONDON — In the sandy expanse of Libya's desert, where temperatures climb above 100 degrees on a winter's day, an army of more than 12,000 foreign workers is toiling on one of the world's most audacious and mysterious public works projects.
Drilling rigs rise 60 feet, their gigantic hammers and powerful bits boring more than a quarter-mile into the earth. Hundreds of trucks haul 75-ton sections of concrete pipe, 13 feet in diameter, which are then lowered into place by huge cranes and buried beneath the sand.
