Three worlds-conceptually

Several beliefs and philosophies endorse the existence of three worlds-namely the one above Earth (say Layer 1), Earth (Layer 2) and Below the Earth (Layer 3).For example in Hinduism there is elaborate description of life below the Earth(Nagalok-where snakes kingdoms exist)and above the earth (Devalok). Forgetting that they have to exist at a level of planets and universe I think there does exist three layers with distinct living styles everywhere. For example the society has three distinct layers-the rich, the middle class and the poor.(I recently read an article and was amazed to find there are three layers even in what we call "Underworlds"-so this concept can be considered universal) Their lifestyles and accepted social practices are governed by their position in society. Similarly when we look at the sea as a world by itself we have three layers-birds that live on the fishes/sea food being the world above, Ocean itself and the one below the ocean floors. I am sure within the ocean itself there are three layers. No wonder functional gods of Hinduism had three responsibilities-create, protect and destroy. This cycle is considered an ongoing process(which is true for organizations too). I was always thinking that Gender is only two but now we start recognize the third gender. What is the significance of this?
I think this is a very important concept to understand as holistically to put everything as ONE is not an ideal approach. To look at it from three different perspectives gives a three dimensional view of issues. For me to look at issues from People, Strategic and operational point of view in that order is key to success of any major decisions. In minor decisions the people part remains but it is the execution and alignment which remains to be focused. Three world theory is a good way to sound our ideas as there are people whose expertise is limited in certain worlds but have friends/well wishers who operate in those worlds. Knowledge connect of worlds is key to success but most of the time there is either no time to do this or impulse governs our decisions. To believe we can rule three worlds is a myth and we need to acknowledge it as true leaders as it the realization of this that makes us look for options beyond what we are usually comfortable with.