Remo Ruffini and Abdus Salam in 1975 established the Marcel Grossmann meetings (MG) on Recent Developments in Theoretical and Experimental General Relativity, Gravitation, and Relativistic Field Theories, which take place every three years in different countries, gathering more than 1000 researchers. MG1 and MG2 were held in 1975 and in 1979 in Trieste ; MG3 in 1982 in Shanghai ; MG4 in 1985 in Rome; MG5 in 1988 in Perth ; MG6 in 1991 in Kyoto ; MG7 in 1994 at Stanford ; MG8 in 1997 in Jerusalem ; MG9 in 2000 in Rome; MG10 in 2003 in Rio de Janeiro ; MG11 in 2006 in Berlin ; MG12 in 2009 in Paris ; MG13 in 2012 in Stockholm ; MG14 in 2015 and MG15 in 2018 both in Rome. Since its foundation, ICRANet has always played a leading role in the organization of those meetings.