Did aliens build the pyramids? This video discusses the mystery and controversy regarding the builders of pyramids found in Cairo, Giza, and around the world as well as the similarities found in the geometric pyramidal structures found on Mars in an area called Cydonia. Cydonia is most famous for the face on Mars image controversy. Featuring Zecharia Sitchin, Richard C. Hoagland, Anthony J. Hilder, Greg Nielsen, Dr. Ron Charles, Todd Alexander, Margaret Morris, David Teuling, and others.