  We propose a holographic description of $\mathcal{N}=4$ super Yang-Mills on
the four-dimensional real projective space $\mathbb{RP}^4$. We first construct
the dual background in the framework of five-dimensional $\mathcal{N}=8$ gauged
supergravity, and then uplift it to a new one-half BPS solution of type IIB
supergravity. A salient feature of our solution is the presence of a bulk naked
singularity whose local behavior resembles that of an O1$_{-}$ plane in flat
space.
