  The emergence and importance of hidden local symmetry in the structure of
hadrons under extreme conditions is discussed. The topics covered are the
potentially important role played by an infinite tower of vector mesons encoded
in holographic dual QCD (or AdS/QCD) in chiral dynamics of mesons and baryons,
in the vector dominance and its violation in EW response functions and the
presence of the vector manifestation fixed point and its influence on the
properties of hadrons in hot temperature (i.e., in relativistic heavy ion
collisions) and in dense matter (i.e., in compact stars). Also discussed are
the natural emergence of instantons/skyrmions from the infinite tower of vector
mesons coupled to pions in AdS/QCD and their (speculated) role in chiral
restoration at high density.
