The Living Arch is a study model that was designed to showcase our ongoing research into bioactive architectural systems to be inhabited by honeybees. The arch is a synergistic combination of 3D printing and active mycelia growth, created for a museum exhibition. It presents (and tests) a subset of our research and development work toward creating living mycelium beehives. The Living Arch exhibits numerous physical, chemical, and biological states in a transparent custom-made box fitted with environmental sensors. It facilitates a visual and olfactory experience of an undergoing slow fungal transformation, which museum visitors could witness and participate in throughout the 6-month exhibition. In this paper, we present the Living Arch as an experimental exhibition piece and a study model of a fungal architecture, as well as the problems that led to the exhibition's early termination.