Pyramids are the greatest architectural achievement of ancient civilization, so people all over the world are curious as to the purpose of such huge constructions. No other structure has been studied as thoroughly, nor have so many books and articles been written about it. We created a computer model of the pyramid. To validate the model, we compare our calculations with the experimental data of Luis W. Alvarez. The fact that the Egyptians set up 2.5 million stone blocks without any purpose seems to be unimaginable. Therefore, we attempt to examine the internal structure of the pyramid using muon tomography. With our measurements we performed and verified a calibration of the attenuation of muons for primary beam momenta of 2.5 GeV/c and 3 GeV/c at the T9 experimental area of CERN.