A sweltering week in late August. Where better to enjoy the last days of summer than on the beautiful Bay of Naples? All along the coast, the Roman Empire's richest citizens are relaxing in their luxurious villas. The world's largest navy lies peacefully at anchor in Misenum. The tourists are spending their money in the seaside resorts of Baiae, Herculaneum and Pompeii. Only one man is worried. The engineer...