Introduction The great pyramids of Egypt and particularly those in Giza have raised more questions on how they were constructed than answers. The manner in which they were constructed is yet to be understood, and every now and then theories spring up to make some explanations. Some of the theories have even proposed that the giant structures were constructed with support from extraterrestrial beings. No single theory explains concisely how these structures were built and thus the pyramids still remain a mystery today. In this article, I will examine two of the theories which have been forward to explain in part the construction of the pyramids. However, I will start by explaining why the construction of the pyramids is a mystery. Lastly, a conclusion is drawn. A Mystery The mystery of the pyramids stems from their gigantic sizes, and the mathematical and structural engineering dimensions which they were constructed with. As at the time of the construction, modern geometry and structural engineering skills that have been discovered to have been used in the construction were not yet known. Constructing a pyramid and ensuring that the four walls meet at a point in a uniform manner is in itself a great feat. The Great Pyramid of Giza is said to occupy a square base of 13 acres. The pyramid was built with more than 2.5 million blocks with each block weighing between 2 to 70 tons each. How these blocks were moved to the construction site and up the pyramid, which is said to be 201 courses up, is a mystery. It is worth noting that modern machinery was not available therefore, all these work was done by manpower (GEP, n.d). Two Theories There are many theories which have been proposed to explain how the pyramids were constructed. Two of the theories are The Inside-Out Theory proposed by Jean-Pierre Houdin and the Transport Theories suggested by Andrzej Bochnacki. The Inside-Out Theory This theory tries to explain how the Great Pyramid of Giza was constructed. According to this theory, the Great Pyramid was constructed in two phases. The first phase involved the construction of the bottom third. At this phase, “blocks were hauled up a straight external ramp to build the pyramid bottom third, which contains most of the monument’s mass” (Handwerk, 2008, p. 1). It is postulated that the construction materials used in the external ramp were used in the construction of the higher parts of the pyramid. It is argued that the reuse of the external ramp materials to construct the higher parts would be a plausible explanation as to why no piece of the ramp has been discovered. The rest of the pyramid was built with the help of “an inclined, internal, corkscrew tunnel, which would continue its path up and around as the pyramid rose” (Handwerk, 2008, p. 1). According to this theory, the tunnel was on the inside and therefore, by the time the pyramid was completed the ramp likewise could not be seen. A notch discovered on the Great Pyramid has been used as a backup for this theory. Another clue which backs up this theory is “an image that looks like a spiraling features inside the structure’s outer walls” (Handwerk, 2008, p. 1). This image was obtained early in 1986 by a French team using the microgravimetry technique. Transport Theories Transport theories were suggested by Andrzej Bochnacki. He proposed ways in which t