  4D Higgs field is identified with the extra-dimensional component of gauge
potentials in the gauge-Higgs unification scenario. $SO(5) \times U(1)$
gauge-Higgs EW unification in the Randall-Sundrum warped space is successful at
low energies. The Higgs field appears as an Aharonov-Bohm phase $\theta_H$ in
the fifth dimension. Its mass is generated at the quantum level and is finite.
The model yields almost the same phenomenology as the standard model for
$\theta_H < 0.1$, and predicts $Z'$ bosons around 6 - 10 TeV with very broad
widths. The scenario is genelarized to $SO(11)$ gauge-Higgs grand unification.
Fermions are introduced in the spinor and vector representations of $SO(11)$.
Proton decay is naturally forbidden.
