Glycine, the simplest naturally-occurring amino acid, exhibits unusually extensive phase diversity. Three polymorphs are known under ambient conditions. Each shows different behaviour at high pressure, the beta and gamma forms transforming to the delta and epsilon phases, respectively. On release of pressure the epsilon phase transforms back to the gamma phase via two new phases. The zeta phase produced initially is short-lived and its structure remains unsolved. This form appears to develop into an expanded form of the epsilon phase (the epsilon-prime phase), which then transforms into the gamma phase. The zeta and epsilon? phases have both been observed in previous beamtime on PEARL, but the data sets suffer from poor statistics. The aim of this beam time is to collect data on both phases suitable for structural analysis of this very unusual sequence of phase transitions.