Great pyramid of Giza is 36524 inches around. If we put decimal point after two digits we get 365.24. This represents the exact number of days of a solar year.
If we divide the circumference by twice the height of pyramid we get pi, accurate to 6 decimal points. It is a very important parameter to many theories that tries to solve mysteries of universe like, Heisenberg uncertainty principle, General relativity of Einstein, Kepler law of orbital motion. And pi was discovered 2000 years after pyramid was built. Did our ancestor really discover pi by themselves. Or they got some help from intelligent alien being?