  Recent experimental results suggest that metallic liquids universally exhibit
a high-temperature dynamical crossover, which is correlated with the glass
transition temperature ($T_{g}$). We demonstrate, using molecular dynamics
results for Cu64Zr36, that this temperature, $T_{A} \approx 2 \times T_{g}$, is
linked with cooperative atomic rearrangements that produce domains of connected
icosahedra. Supercooling to a new characteristic temperature, $T_{D}$, is shown
to produce higher order cooperative rearrangements amongst connected
icosahedra, leading to large-scale domain fluctuations and the onset of glassy
dynamics. These extensive domains then abruptly stabilize above $T_{g}$ and
eventually percolate before the glass is formed. All characteristic
temperatures ($T_{A}$, $T_{D}$ and $T_{g}$) are thus connected by successive
manifestations of the structural cooperativity that begins at $T_{A}$.
