Hmm....burial sites? I think that the existence of the Pyramids is much deeper than that. With the fact that they were built on the world's electro-magnetic fields, could it mean that these humans involved in erecting these architectural masterpieces knew more than we know (or publicly say that we know)?
Here's an old black and white film sequence of the pyramids and Sphinx at Giza, Egypt from award-winning amateur filmmaker John V. Hansen's travel footage, c. 1926-1930. The Pyramids at Giza are a UNESCO World Heritage Site. They are the only site from the "Seven Wonders of the Ancient World" list that are still in existence, and are an Honorary Candidate of the "New Seven Wonders of the World." The film clip is from the Human Studies Film Archives, Smithsonian Institution collection of historical moving images.