ɪnðə nˈaɪntiːnhˈʌndɹɪd sˈɪksti z ænd nˈaɪntiːnhˈʌndɹɪd sˈɛvənti z, θɹuː ɪlˈiːɡəl lˈɪɾɚɹᵻtʃɚ pˈʌblɪʃt ɐbɹˈɔːd, ænd ðˈɛn θɹuː sˈæmɪzdˌæt, ðə kˈɑːnsɛpts ʌv "kˈæɾɐkˌoʊmz" ænd "kˈæɾɐkˌoʊm tʃˈɜːtʃ" ɹᵻtˈɜːnd tə ðə jˌuːˌɛsˌɛsˈɑːɹ.
In the 1960s and 1970s, through illegal literature published abroad, and then through samizdat, the concepts of "catacombs" and "catacomb church" returned to the USSR.