Obelisks are four-sided monolithic pillars that taper slightly from the base to the top. These monuments were designed to impress with their height and last forever; Its construction required an extraordinary investment in labor and required a vast deployment of engineering; and were loaded with religious and political symbols and messages 1.
The pyramids, on the other hand, are funerary monuments that were built to house the mortal remains of the Egyptian pharaohs. The Great Pyramid of Giza is the largest and oldest of the three pyramids located on the Giza Plateau near Cairo. It was built during the reign of Pharaoh Cheops, around 2560 BC.
In short, although it is an interesting idea, there is no historical evidence to support the theory that the pyramids were just the heads of larger obelisks buried underground. However, both obelisks and pyramids are impressive monuments that reflect the rich history and culture of ancient Egypt.