2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/117811We prove that the boundary of a right-angled hyperbolic building is a universal Menger space. Corollary: the 3-dimensional universal Menger space is the boundary of some Gromov-hyperbolic group.35 pagesGeometric Topology20E42; 54F35; 20F67text