Using modern high-pressure technology, a plethora of fascinating effects can be induced in chemical systems. Pressure in the gigapascal range (1 GPa ≈ 10 5 atm) may cause electronic rearrangements at the atomic level, allows the synthesis of otherwise unobtainable chemical compounds, gives access to novel crystal structures, and leads to the metallization or polymerization of substances. The experimental method of choice in high-pressure chemistry, physics and materials science is the diamond anvil cell (DAC), which allows the constant application of pressure up to a few hundred GPa. Due to this enormous pressure range, even planetary interiors can be modeled with a DAC.