I heard an interesting theory that the top of Sigiriya was the place where "ancient gods" loved to relax and had fun with sexy young girls in pools filled with cool water.
They were getting to the top with the help of flying machines aka vimana.
Interestingly, the very top of the mountain looks like geometrically regular rectangle and has a plain surface for landing of a flying machine, for example a modern helicopter.
I visited Sigiriya in June 2017. It was extremely interesting experience.
What a lovely place with stunning views!
Here is my photo in the middle of the hard way to the top.