Recent developments in magnetic flux tailoring techniques paved the way for NMR in high pressure diamond anvil cells at multi-megabar pressures. NMR resonator structures based on the principles of recently developed Lenz lenses can be realized with high spatial resolution on the surface of the diamond anvils. These structures have been demonstrated to combine the mechanical robustness and spin sensitivity required for geophysically extreme conditions, i.e. pressures well above 100 GPa and temperatures above 1000 K. Here we present our work of the last 3 years at the Bavarian Geoinstitute which led to this major technological advancement.