  Extra-dimensional theories contain additional degrees of freedom related to
the geometry of the extra space which can be interpreted as new particles. Such
theories allow to reformulate most of the fundamental problems of physics from
a completely different point of view. In this essay we concentrate on the brane
fluctuations which are present in brane-worlds, and how such oscillations of
the own space-time geometry along curved extra dimensions can help to resolve
the Universe missing mass problem. The energy scales involved in these models
are low compared to the Planck scale, and this means that some of the brane
fluctuations distinctive signals could be detected in future colliders and in
direct or indirect dark matter searches.

High Energy Physics - Phenomenology;Astrophysics;General Relativity and Quantum Cosmology