  The LHC brings nuclear collisions to the TeV scale for the first time and the
first data show the qualitative differences of this new regime. The
corresponding phase-space available encompasses completely uncharted regions of
QCD in which high-density or high-temperature domains can be identified.
Proton-nucleus runs are essential for a complete interpretation of the data and
for the study of new regimes dominated by large occupation numbers in the
hadronic wave function. I comment here the physics opportunities for p+Pb runs
at the LHC and d+Au runs at RHIC and the corresponding needs in view of the new
Pb+Pb data from the LHC.
