Egypt's Obelisks: Part Of An Ancient Energy System?

The obelisks of Egypt are believed by many to be artifacts of the Dynastic Egyptians.

However, since said people in general only had bronze age technology, how could they have quarried, shaped, moved and erected such massive single pieces of stone?

The answer could be that an earlier, and far more technologically sophisticated culture made them, and the Dynastic Egyptians inherited and claimed them.