Where is the mantle located and what is it made of?

Could you please elaborate on the location and composition of the mantle? I'm particularly interested in understanding its placement within a given context, whether it be geographical, astronomical, or perhaps even metaphorical. Furthermore, I'm curious as to what materials it might be constructed from. Is it a physical entity, composed of tangible matter, or is it more abstract, perhaps a concept or idea? Your insights would be greatly appreciated as I seek to gain a deeper understanding of this enigmatic mantle.