Ideas of Hidden Naturalness have received tremendous interest in the past few years. Comparing to classical Naturalness models based on Supersymmetry, Hidden Naturalness scenarios solve the Higgs Hierarchy Problem and remain mildly constrained by existing searches. Scenarios in this type, however, do provide striking signatures in both collider and cosmology. In this talk, I will focus on a variety of Twin Higgs models, which are representative scenarios of Hidden Naturalness, and discuss their collider signature from long-lived particle searches. For the scenarios that do not leave visible signals at colliders, I will explain how cosmology and direct detection experiments can probe the existence of a dark Universe that is predicted by the Twin Higgs models.