Designed by giants,
made by Giants...Occam’s Razor...
Just like the pyramids ...The most logical simplest solution is usually the true solution.
No, it’s not, since internal space of megalithic structures are barely adequate for modern humans, and therefore — by Occam’s Razor — wouldn’t have been appropriate for giants. The architect of the Great Pyramid was buried on the Giza Plateau, and the tomb isn’t giant sized.