This is so easily researched I wonder how lazy the questioner is or how far the scope of debate can go. There are huge villages built just to house the workers who built the pyramids google them. And no the pyramids were not built by slaves, those who built the pyramids were free men and women who worked for pay.
Archaeologists have long studied the Egyptian pyramids. Many have concluded that the amount of labor necessary to build the pyramids would have required slave labor. It was very common for the great empires of the ancient world to employ slave labor for major projects. In short, yes, there is some proof that the pyramids were built by slaves.
No, there is not real proof that the Great Pyramids were built by slaves. There is also not proof that they were not built by slaves. This happened too long ago for people to ever get an answer to this question. Furthermore, it is insignificant now as they have been dead for hundreds of years.
I am finding it hard to believe the Egyptians had the capability to build the pyramids with the resources available to them at the time. Stone as heavy as 9 tonnes was moved by using just wood and rope? Seems a bit too far fetched for my liking. You do know that people have recreated moving stone like that using Egyptian methods and it works, right? You also know that there is construction by scientific teams in Egypt now using all ancient methods....right? No. There is no alternative "evidence" No one ever questions the great cities of the Roman Empire. Their strength and intelligence still influence us today. Why would ancient Egypt be any different?
As it is with any topics dealing with the ancient world, there is no way to guarantee absolute certainty that the pyramids were built by slaves. Research, archaeological discoveries and historical accounts can only do so much to teach us about the past. I believe that at this time, the is insufficient proof to determine with absolute certainty that the pyramids were built by slaves.