This is the hinge point of it all really. People say alien's; what alien's show me the proof. I think it was Synch who made the point. This picture is definitely Inca and not alien:
Everywhere you go in the UK you see dry stone walls or similar constructions. You can trace this exact style of architecture very close to our time.
This however is different:
There is nothing remotely recognisable in this. Nothing even remotely matches it over the last few thousand years to my knowledge. It has no modern analogue whatsoever. Not just huge blocks but small too:
'We' just do not do this. We do other architecture. Recognisable as Roman, Greek, Renaissance, take your pick. But not these above.
In this sense the above work is well and truly 'alien'.
The cap fits you see.
Unless they used too much coca leafs? Or some other substance which disort them their perception.