Inca Gold by Clive Cussler

When a tsunami hit a Spanish treasure galleon, all trace of a golden hoard greater than that of any pharaoh's vanished into history. Until NUMA agent DIRK PITT dives into an ancient sacrificial pool far into the Andean jungle in order to rescue two archaeologists, and plunges into a vortex of corruption, betrayal, and death. A sinister crime syndicate has traced the long-lost treasure -- worth almost a billion dollars -- from the Andes to the banks of a hidden underground river flowing beneath a Mexican desert. Nothing will stop their ruthless and murderous drive to recover the gold. Nothing, that is, until Pitt and his team place themselves square in the path of danger....

Approved by Englishcology