  Based on the observation that the dimension of the tangent space is not
necessarily equal to the dimension of the corresponding curved manifold and on
the known fact that gravitational theories can be formulated in a gauge
theoretic way, we discuss how to describe all known interactions in a unified
manner. This is achieved by enlarging the tangent group of the four-dimensional
manifold to $SO(2,16)$, which permits the inclusion of both gauge groups, the
one that describes gravity as a gauge theory as well as the $SO(10)$ describing
the internal interactions. Moreover it permits the use of both Weyl and
Majorana conditions imposed on the fermions, as to avoid the duplication of
fermion multiplets of $SO(10)$ appearing in previous attempts. The gravity
theory discussed in the present work is the Conformal Gravity which, after a
spontaneous symmetry breaking, can lead either to Weyl Gravity or to the usual
Einstein Gravity.
