High-pressures can be created with a piston-cylinder apparatus, up to 5 GPa (50 000 bar) and ~2000 °C.
The piston is shifted with hydraulics, decreasing the volume inside the confining cylinder and increasing the pressure.
For higher pressures, up to 25 GPa, a multi-anvil[1] cell is used and for even higher pressures the diamond anvil cell.
The diamond anvil cell is used to create extremely high pressures, as much as a million atmospheres (101 GPa), though only over a small area.
The current record is 560 GPa, but the sample size is confined to the order of tens of micrometres (10−5 m).