  Updated data of the 153 Galactic globular clusters are used to readdress
fundamental parameters of the Milky Way. We build a reduced sample,
decontaminated of the clusters younger than 10Gyr, those with retrograde orbits
and/or evidence of relation to dwarf galaxies. The 33 metal-rich globular
clusters of the reduced sample extend basically to the Solar circle and
distribute over a region with projected axial-ratios typical of an oblate
spheroidal, $\rm\Delta x:\Delta y:\Delta z\approx1.0:0.9:0.4$. The 81
metal-poor globular clusters span a nearly spherical region of axial-ratios
$\approx1.0:1.0:0.8$ extending from the central parts to the outer halo. A new
estimate of the Sun's distance to the Galactic center is provided, $\rm
R_O=7.2\pm0.3 kpc$. The metal-rich and metal-poor radial-density distributions
flatten for $\rm R_{GC}\leq2 kpc$ and are well represented both by a power-law
with a core-like term and S\'ersic's law; at large distances they fall off as
$\rm\sim R^{-3.9}$. Both metallicity components appear to have a common origin,
which is different from that of the dark matter halo. Structural similarities
of the metal-rich and metal-poor radial distributions with the stellar halo are
consistent with a scenario where part of the reduced sample was formed in the
primordial collapse, and part was accreted in an early period of merging. This
applies to the bulge as well, suggesting an early merger affecting the central
parts of the Galaxy. We estimate that the present globular cluster population
corresponds to $\rm\leq23\pm6%$ of the original one. The fact that the
volume-density radial distributions of the metal-rich and metal-poor globular
clusters of the reduced sample follow both a core-like power-law and S\'ersic's
law indicates that we are dealing with spheroidal subsystems in all scales.
