Associated to a Calabi--Yau (e.g. abelian varieties, K3 surfaces), one can associate an essential skeleton, which lives in the Berkovich analytification of the Calabi--Yau. This skeleton originates from mirror symmetry and captures geometrical and topological information of the Calabi--Yau. For example, it is related to the birational geometry of the Calabi--Yau, and in some situations the Calabi--Yau admits a Lagrangian fibration over this skeleton.
We will only assume knowledge of the definition of Calabi--Yaus and will introduce by examples.