1.) Don't know
2.) The Trojan Horse is mentioned by Homer in the Odyssey and describes the stratagem that allowed the Greeks to penetrate the citadel of Troy and sack the city. Homer attributes the idea to Odysseus who is said to have the greatest mind of all the Greek captains.
3) The Pyramids is a device used by the Pharaohs of Egypt to obtain immortality. Firstly it is a visible monument to their reign, which people who come after them will always see and thus remember there name. Secondly some believe that the soul of the dead king beneath would climb to the apex of the pyramid and join with the sun God Re as he passed overhead.