Karmic retribution? (spoilers)
I know I'm reading way too much into it, but: At movie's end, just as Professor Catalan unearths the cache of diamonds, a series of explosions send the rocks tumbling, killing him. What seems to be an ancient curse turns out to be dynamiting for a new road.
The movie doesn't imply it at all, but I imagine the roadwork construction is tied in with new development organized by the late De Castro (the archaeological expedition he funded may well have been part of the whole deal), in effect having him avenge his own death.
Just a pet theory here. I actually liked De Castro - he was pompous and condescending, but also generous and expansive. I really felt bad when he was murdered.