  A sufficiently large perpendicular magnetic field quenches the kinetic
(Fermi) energy of an interacting two-dimensional (2D) system of fermions,
making them susceptible to the formation of a Wigner solid (WS) phase in which
the charged carriers organize themselves in a periodic array in order to
minimize their Coulomb repulsion energy. In low-disorder 2D electron systems
confined to modulation-doped GaAs heterostructures, signatures of a
magnetic-field-induced WS appear at low temperatures and very small Landau
level filling factors ($\nu\simeq1/5$). In dilute GaAs 2D \textit{hole}
systems, on the other hand, thanks to the larger hole effective mass and the
ensuing Landau level mixing, the WS forms at relatively higher fillings
($\nu\simeq1/3$). Here we report our measurements of the fundamental
temperature vs. filling phase diagram for the 2D holes' WS-liquid
\textit{thermal melting}. Moreover, via changing the 2D hole density, we also
probe their Landau level mixing vs. filling WS-liquid \textit{quantum melting}
phase diagram. We find our data to be in good agreement with the results of
very recent calculations, although intriguing subtleties remain.
