This presentation will describe a new material paradigm: contiguous, atomically-thin, epitaxial metal films, one monolayer to several multilayers thick, where the graphene serves as both the growth template for the metal films and also as a ‘chemically transparent’ barrier against catalytic deactivation. In the latter role, graphene does not restrict access of the reactants to the catalyst but blocks the catalyst from dissolution or agglomeration. In other words, a true 2D atomically-thin metal is demonstrated - which the author believes is a first in the scientific community. A fundamental questions we can ask ourselves is whether surface metal atoms rendered in these 2D architectures are as stable as those of their counterparts in bulk. In the Pt/graphene case it is found that the surface atoms exhibit stronger binding than their bulk counterparts, but do so without sacrificing metal-like Fermi level electronic structure. The bulk-like stability of atomically-thin Pt/graphene is possible through a combination of inter-planar Pt-C covalent bonding and inter/intra-planar metallic bonding. It is further shown in a related system that by introducing a single-layer of graphene as an interface between the core and surface metal layers, unwanted surface alloying between the layered metals can be mediated. The room-temperature epitaxial synthesis approach has immediate implications on the science and application of metal catalyst systems that are support-flexible in design. More broadly, however, we reveal a new frontier for the nature of metals themselves, where they can be rendered in 2D films that are single to several atoms thin and are supported on a movable, electronically coupled substrate. Such metal/graphene or graphene/metal architectures will impact not just catalysis, but also electronic, thermoelectric and optical materials