First off all this is just my opinion on all of the mysterious events on Earth that have trouble all scientists around the world. Supposedly all of these artifacts were found and scientists could figured out how it was invented, or why was it invented. Also some structures were also also strangely build, and archaeologists have no clue on how was it construct. This is my theory for all of this madness.
The things that troubled most of people are the Pyramids, no one had gave a clear theory on how was it built. Some other wonders included the Stonehenge, The Sphinx, or the Easter Head Island. Those construction cannot be explained. I used to thing it was fairies who did those (may be), but on the science standpoint, I would say this was purely man-made. I believed that Earth years start really early, even before our calculated time, and it had been developed to the kind of world that is similar to today, only the perspectives were different. What I mean is, may be we already have cars, crane (used to build large structure), clocks (Antikythera watch)… Those things were invented and used wisely, but at a point of time, a really big earth quakes or meteorite struck the Earth and wiped the world completely away, a few humans survived, and the world keep on going without the lost story. The leftovers are some structures, The Pyramids, The Stonehenge, the Mayan’s tower… That is my theory because, I don’t think that people in 300 hundred years ago till today can developed a train to a Ferrari car, but not the people 100 million years ago. Soneone say that the purposes for the building cannot be defined, I would say that they can be used for something we cannot understand, because people had a different mindset 100 millions years ago.
I’m no scientist, this is just my theory, it likely to be wrong, but who cares right! Please fell free to add anything, but if my theory somehow correct, and I heard it in the news, somebody will be in trouble 🙂