If ever there were a structure built to stand the test of time, it surely would be the Great Pyramid of Giza, a transcendent monument to human imagination and ambition. Since being erected during the Old Kingdom period of ancient Egypt, it has stood impassively as time marched on and civilizations rose and fell.

Hard limestone rock used to build the pyramid is reducing its risk of damage, scientists suspect

Somehow, while the rest of the ancient Egyptian world has crumbled around it, the Great Pyramid of Khufu at Giza remains standing, even after 4,600 years.