Aliens and Unexplained Engineering

Across nearly every continent on Earth we can find similar remarkable stone structures of unexplainable engineering feats. Might the building of these megalithic sites have been directed by an extraterrestrial hand, as Ancient Astronaut theorists have long proposed? From the curious discoveries made at the Great Pyramid, at Teotihuacan and Stone Henge, new evidence may suggest that these structures are not only connected, but also part of a more profound--and powerful--network.