The deepest bridge foundation ever built stands in 65 meters of water. The stretch of sea between Italy and Albania is 800 meters deep at its shallowest point, and the channels pass 1,000. That one number is why this bridge will never exist. The rest of the math only gets wilder. The Strait of Otranto is 72 km across. The longest sea crossing on Earth, Hong Kong to Macau, runs 55 km over water that mostly stays under 40 meters deep, so engineers could sink piers like fence posts. At Otranto,…