  We present some modern theories on the structure of spacetime that can be
classified as relational theories in the direction of Leibniz's ontology. In
order to analyze the nature of spacetime we consider three levels of knowledge
-observational, theoretical and ontological- to which the different models can
be adscribed. Following similar approach to these models mentioned at the first
sections, we present our theoretical model of the structure of spacetime, some
physical applications, and the ontological interpretation of the model.
