Abstract: The idea behind the limiting curvature hypothesis is that there shouldexist a fundamental length scale, probably of the order of the Plancklength, that sets a bound on all curvature invariants. Constructing atheory that satisfies the limiting curvature hypothesis would thereforebe free of singularities, e.g. including the Big Bang initialsingularity and the singularity at the center of black holes. Buildingsuch theories is not a trivial task, and existing models either fail atavoiding all divergences at the background level or have instabilitiesat the perturbative level. In this talk, I will review an apparentlyunrelated modified theory of gravity, the cuscuton, which proposes toadd an incompressible scalar field with a non-canonical kinetic term tostandard general relativity. I will review the properties of thecuscuton and show how it represents a limiting curvature theory in acosmological setup, hence leading to non-singular solutions. I will thenpresent aspects of the cosmological perturbations in various gauges,addressing several issues including that of stability and the(in)validity of certain gauges at different points in time across thecosmological evolution.