The Pyramids Mystery Resolved - Meme and a Question

For millenniums, the mystery of the great pyramids in Egypt puzzled the world, it took the imagination of a one person recently to decipher it:

Since the above is obviously a meme which I liked to share with you, credit to its author who obviously knows something about the Egyptians and their love for cats, the real question is not what the pyramids were built for, rather: how they were built, and why there are pyramids in different locations in the world?

Do share your thoughts on these two questions.