  We report detailed low temperature magnetotransport and magnetization
measurements in MnSi under pressures up to $\sim12\,{\rm kbar}$. Tracking the
role of sample quality, pressure transmitter, and field and temperature history
allows us to link the emergence of a giant topological Hall resistivity
$\sim50\,{\rm n\Omega cm}$ to the skyrmion lattice phase at ambient pressure.
We show that the remarkably large size of the topological Hall resistivity in
the zero-temperature limit must be generic. We discuss various mechanisms which
can lead to the much smaller signal at elevated temperatures observed at
ambient pressure.
