Brien Foerseter - The Pirwas - Pre-Cataclysm Builders of Peru.
so, let's look back in Evolutionary Time:
we'll travel back in time from today's Technological Age back to the Second World War or Nuclear Age back to the Factory/Industrial Revolution back through the Middle Ages to the Iron Age and the Bronze Age Warrior Empires and client Farmer Kings right back to the use of stone/flint tools which Hunter-Gatheres used to kill and skin animals, to chop trees for temporary huts...
But wait, what is this?
Someone from a FAR SUPERIOR TECHNOLOGICAL AGE carved these pre-Cataclysmic Peruvian Stone Structures in one of the hardest stones we have Andesite i.e. harder than granite.
Now, it's the same with Egypt's Sphynx, massive construction of stone monuments LOOOOOONG before what we now call Modern Society or Communal Gatherings are said to have evolved. Humans or some-other-variant from within or without the Solar System used to know how to do this, used to have the technology to drill, sculpt, move tonnes of andasite.
12,000 years ago, something really terrible happened to this planet be that a space-arrived cataclysm or some form of Ancient Nuke War between rival alien factions, and this level of human evolution was wiped out, taking with it The Masonic/Technological Knowledge.
FURTHER VIEWING: if you want a more intensive version of the above 'question's about Inca Architecture and Technology, watch this more in-depth presentation by Brien Foerster.
Personal highlight from this presentation was the suggestion that 'due to the surface perfection of the stone carving' the Ramses-attributed statues, tombs and obelisks are actually from a far-earlier and far-more-advances Machine Tooled era, in comparison with the builders of the stone monuments from Peru and elsewhere.