How did the egyptians build the pyramids bare handed?

Most people have the conspiracy that aliens help the Egyptians built the great pyramids of Egypt due to some artifacts and discoveries of archeologists now and then. But according to the Bible, with a lot of help from the slavery of Israelites and architectural plan of Egyptians- the pyramids were built. Thus, with many discoveries, it is proven that people of their time worked together to build these pyramids. Wall paintings and illustrations show the early architectural man-made machines that they used in building that are mistaken as belong to the aliens. It is so amazing how do they build the great pyramids of Egypt with their bare hand but anything is possible with unity and technology, even with early technology. 

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It was difficult, tense and violent as the settlers arrived.