Synchrotron radiation facilities around the world which have nuclear resonant scattering (NRS) beamlines (solid blue symbols): 1 = ESRF, with 6 GeV electron energy and 0.9 km circumference, operating since 1994; 2 = APS, with 7 GeV electron energy and 1.1 km circumference, operating since 1995; 3 = SPring-8, with 8 GeV electron energy and 1.5 km circumference, operating since 1996; 4 = Petra–III, with 6 GeV electron energy and 2.3 km circumference, operating since 2009. The gray circles indicate the possible NRVS-suitable rings in the future: A = HEPS, with 6 GeV electron energy and 1.4 km circumference; SKIF, with 3 GeV electron energy and 0.5 km circumference.