  The search for solutions of Einstein's equations representing relativistic
cosmological models with a discrete matter content has been remarkably fruitful
in the last decade. In this review we discuss the progress made in the study of
a specific subclass of discrete cosmologies, Black-Hole Lattice models. In
particular, we illustrate the techniques used for the construction of these
spacetimes, and examine their resulting physical properties. This includes
their large-scale dynamics, the dressing of mass due to the interaction between
individual black holes, along with features of direct observational interest
such as the distance-to-redshift relation. This collection of results provides
a novel perspective on the physical effects of averaging in General Relativity,
as well as on the emergence of gravitational structures from solutions with
isolated objects.
