  We establish universality and ultra-homogeneity of
$(\mathcal{U},u_\mathrm{GH})$, the collection of all compact ultrametric spaces
endowed with the so-called Gromov-Hausdorff ultrametric. This result also gives
rise to a novel construction of the so-called $R$-Uryoshn universal ultrametric
space for each countable subset $R\subset\mathbb{R}_{\geq 0}$ containing $0$.
