2018 marks the exciting 85th birthday celebration of the “Keggin structure”, which itself is at the center of polyoxometalate (POM) chemistry! The first polyoxoanions were reported almost two centuries ago by Berzelius (1826), but J. F. Keggin could only characterize them structurally in 1933 [1]. He solved the structure of the free acid H3PW12O40 using powder X-ray diffraction, a highly symmetrical metal-oxo anion with tetrahedral symmetry (see Fig. 1). The availability of X-ray diffraction techniques paved the way for the discovery of a large number of novel POMs with different shapes and sizes. Keggin is our POM pioneer!