Puma punku, Bolivia. Oldest structures on EARTH. Aprox. 14-17,000 years old & built with construction techniques unknown. Only diamonds are strong enough to cut these stones. Modern diamond tipped drills powered by computers and assisted with heavy machinery today would have great difficulty replicating the stone work.
Puma Punku in Tiahuanaco - I do not think ''aliens'' were responsible for building this site, but I think ancient man was far more advanced than we as yet understand. The technology needed here was way beyond any later civilisations.
A 10-ton gateway to the temple nearby was carved from a single rock and has elephants and toxodons carved into it. The toxodon is a large grazing creature that resembles a hippo with a longer neck. Both it and the South American elephant (Cuverionius) have been extinct since 11,000 to 12,000 BC.