Final answer:
The best example of grottos' twofold vision of the divine and human is Medieval architecture, particularly Gothic art and architecture, as showcased by sculptures at Chartres Cathedral.
Step-by-step explanation:
In exploring grottos' twofold vision of the divine and human through medieval architecture, we find that Gothic art and architecture frontiers the communion of spiritual and worldly motifs. As exemplified by Chartres Cathedral in France, the monumental sculptures adorning the portals and facades embody theological narratives while embracing humanity's emotions and virtues. These art forms invoke a teaching function that extends beyond liturgical congregations, reaching both the literate and illiterate populace of the period.
As medieval sculpture evolved, its alliance with architecture became more pronounced, culminating in masterworks like the tympanum at Autun Cathedral. This integration not only demonstrates the craftsmanship of sculptors who may have begun as masons but also the integrative approach of imbuing sacred buildings with compelling narratives and spiritual schema. These cathedrals and sculptures collectively manifest the dual representation of the divine — transcendent and imminent, thereby providing a clear example in response to the given question.