The most extreme treatment of minorities has been carried out by 20th- and 21st-century dictatorships. The worst examples are those of totalitarian regimes that carried out genocide to eradicate unwanted groups in society. The Holocaust perpetrated by Nazi Germany murdered six million Jews, one-third of the total world Jewish population, as well as a significant portion of the Roma ("Gypsy") community. Homosexuals were also a targeted minority for extermination. The Soviet Union, under Stalin, carried out mass executions and deportations of dozens of Caucasian and Central Asian ethnic groups; some now face extinction.