How were the Egyptian Pyramids built ?

Egyptian Pyramids is one of the most important ancient civilization in the world and everyone is interesting on those Pyramids were built by what method.

1 ) Use body’s strength with leverage principle only to pull or lift up those big stones ?

– The use of slopes :
Place some rollers only under the stone, is it enough helpful to let people pull up the big stone on the slope easily ? ( I think the weight of one big stone maybe heavier than a truck )

– The use of gear lifting :
The height of the pyramid is same as some building, and each stone is also very high and heavy. I think it needs to design a tool as like as tower crane for this project firstly, but it is possible to build up this tool at the ancient time which has not enough resources ? ( If there had such the tool, why do we not found any remnant today ? )

2 ) By the change of natural environment – based on past experience that there will be a rising of water level appeared per few years, and then move the floating stones up level by level in this period ?

– The arrangement is too complex, and it need to have an accurate planning, is it possible?
In case there is not enough water rising level or water back too fast, they need to give up and then wait for next time ?

– When the stone is floating in the water, human can control the moving direction of the big stone easily ?

3 ) Assistant by a mysterious power ?

1) and 2) are coming from some of the so-called experts who like force to figure out and explain some reason after discovered something every time. Actually, did they use the rationality, logic and opportunity rate to analyze included ? Imagination is always easy.
If not 1) and 2), there is really no other way to speculate that they should get an assistant of mysterious power, is God ? Is an Alien ?

In conclusion:

If not 1), 2) and 3), … then I think those ancient people should be really super-wise, because they could build a pyramid which today’s people still do not figure out how to do it with limited resources at that time !