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.
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.