The size and antiquity of the pyramids makes them an irresistible source of mystery & wonder. I've studied many different theories on their construction & purpose, and I think some ideas are more likely than others.
The Monkey Buddha Archives:
I found this digital painting at Letter from Mad Plato, showing cybernetic aliens supervising the construction of the pyramids using advanced technology. It's fun to wonder about the possibilities, no matter how outrageous they may seem.
Despite the staggering scope of these immense (& seemingly superhuman) structures, I am pretty confident that their creation is well within the engineering capabilities of ancient humans.
During my search, I also watched this video that makes a compelling case for the use of hydraulic engineering in the construction of the Great Pyramid. I think this theory by Chris Massey is definitely thinking outside the box. There are some obvious problems with the ideas presented, but it's more likely that the pyramid builders used the laws of nature more than other-worldly alien tech.
The pyramid's limestone blocks being floated through the Nile-fed water channels,
using air-filled animal skins bundled with papyrus.
A hydraulic lock in an enclosed water channel, going up the side of the pyramid.
The floating blocks would rise to the top of the construction using natural buoyancy.
A glaring question about this theory would be: How would the Egyptians have created enough pressure to maintain such a massive column of water, while also preventing the walls of the channel from bursting? The Romans were able to get water to flow uphill for short distances, but this seems like a much more difficult feat.
Regardless of how it was built, the fact is that it was built- using some combination of forces and technology. By using human ingenuity, ancient builders understood that natural forces could be used to do the work, instead of teams of men of animals.
Although the Great Pyramid and other ancient structures will always have an element of mystery, we will continue to unravel their secrets as our own knowledge & wisdom as a species grows.