The structural behavior of the Zr₅₂Ti₅Cu₁₈Ni₁₅Al₁₀ bulk glass has been investigated in situ by means of high-temperature X-ray synchrotron diffraction. The crystallization starts with the formation of an extremely fine nanostructure followed by the transformation into tetragonal NiZr₂-type crystals plus an unknown phase. Both phases are metastable and transform at about 1123 K into the stable equilibrium phases. The temperature dependence of the scattering curve I(q) of the glass can be well described within the framework of the Debye theory. At the glass transition the first derivative dI(q)⁄dT changes. A Debye temperature θ=412 K was estimated for the glassy, and θ=162 K for the liquid state of the Zr₅₂Ti₅Cu₁₈Ni₁₅Al₁₀ alloy. The short-range order of the glass, of the supercooled liquid state, and of the equilibrium melt at T=1193 K is found to be quite similar. The results point to the formation of complex chemically ordered clusters already in the melt.