Oi! I mentioned the astronomy aspect 
Actually, that's part of it is completely fascinating. What do you know about it, please?
well I'd have to look up some stuff to get all the details, but off the top of my head
The three pyramids at Giza appear to be built on the pattern of Orion's belt. The main entrance shaft of the pyramid lines up with the polar celestial sky.
The sides of the pyramid align almost perfectly with true north and the cardinal points of the compass, even today with modern equipment, we would have difficulty achieving the same level of accuracy. In order to achieve this, they would have had to have either immensely advanced knowledge of the earth, technology way beyond what anyone thinks they had, OR they had to have complex astronomical knowledge in order to calculate from the stars exactly what true north was (keeping in mind that the pole stars change over time. They could not simply look at Polaris because it wasn't the pole star in the ancient past.)
The entire pyramid is essentially a square circle, meaning it is built on the mathematical principle of pi,which supposedly hadn't been discovered yet.
Its dimensions supposedly contain calculations which show the curvature of the earth, the circumferance of the earth, and the distance from the sun to the earth.
Going back to the more historical mysteries, for a moment. One of the oddities of the pyramid is that the supposed 'burial' chambers were sealed with a granite plug stone that appears to have been put in place during the construction, not afterwards. Which would have made it impossible to actually burry anyone in it once it was built.
Also, egyptian burials made use of magical inscriptrions supposed to assist the pharoh in his journey to the after life. These were originally painted inside the pyramid tombs (now called pyramid texts) and later on they began inscribing them on the coffins themselves, (called coffin texts). The great pyramid contains no pyramid texts at all, no heirogliphics of any kind. This, again, is very unusual for egyptian sacred buildings which were usually covered with heiroglyphs.
another interesting fact is that prior to the great pyramid the pyramids built by the egyptians were rudimentary at best. Then all of the sudden the great pyramid appears on the scene, literally so perfect that we have difficulty recreating it today if we tried. Then after the giza complex is complete, the pyramids go back to rather poor rudimentary buildings and finally cease.
If the great pyramid was built as claimed, the person who designed it and over saw its construction, in that time period, with what he had available, would literally have to be the smartest man who ever lived, not even kidding.
He would have had to have mathematic and astronomical knowledge far beyond what anyone else of that era knew, he would have had to have advanced knowledge of stone work and a method of cutting and shaping stone which is still unknown to us today. Not to mention a method of moving and placing the stones.
Some of the stones in the pyramid are so large that even today there are only a few cranes in the entire world capable of lifting them, and for ONE LIFT of that magnitude it takes a week to prep. One week for EACH LIFT.
earlier I mentioned that the stone of the great pyramid was harder than the copper tools available. Most of the stone could have been cut with hard bronze tools, which archeology tells us did not exist at that time. However the granite within the pyramid is so hard that today it has to be cut using diamond tipped cutting tools. We are supposed to believe that this was cut with stone tools.
Many peolpe don't know it now, but until the middle ages the pyramid had an outer shell of pure white limestone. This was stripped off by the muslims to use in reparing Cairo after an earthquake.
Three different historical sources tell us that the outer casing stones of the pyramid were covered with strange inscriptions that were not heiroglyphs or any known egyptian language or alphabet. Herodotus reported this in around 430 BC, it was again reported by a Muslim Historian in the 12th century and a european traveler of the 14th century. The muslim historian said that the inscriptions on the exterior of the pyramid were enough to fill thousands of pages of writing.
There are 2,600,000 stones in the great pyramid, ranging in weight from 10 tons to 70 tons.
Egyptologists tell us that the pyramid was not built by slave labor, but rather by egyptian labor crews who worked during the months when the nile was flooded and they couldn't tend the fields. This leaves them about 3 months a year of work time. We are supposed to believe that the pyramid was built during this time.
Ok.. lets take a look, we'll assume that they worked 24 hours a day, which is not particularly likely, but we'll assume they really really were motivated and so they had full work crews going even at night (extremely unlikely). Today, it would take a crew hours to place even the small stones, and up to weeks for the large stones. For the sake of argument, however, we'll assume that the ancient egyptians with rudimentary engineering knowledge and no advanced math skills managed to figure out how to place the blocks much faster, we'll say a nice round number of 30 minutes per block.. thats not cutting them and shaping them, but simply rolling them into place from wherever they were being stored and shaped etc.
Given those assumptions, which by most standards are rediculously generous, it would have taken 601, almost 602 years to build the pyramid. Even if they worked a full year, instead of the few months every year that all historians agree was the case, it would have taken over 150 years. Much longer than is allowed by the accepted version.
Keep in mind that Khufu's son khafre supposedly built the next biggest pyramid (and the sphynx) sitting next to the great pyramid during his reign, so supposedly this was completed within the life time of Khufu, or very shortly after his lifetime.
There are only two possible conclusions.
#1 the builders some how figured out a way to lay massive stones with a high degree of precision at literally lightning speed.
#2 the pyramid took much longer to build than current history allows and as such it does not fit within the scope of the current version that Khufu built the great pyramid and Khafre finished the Giza complex.
