ɐkˈoːɹdɪŋ tʊ ɐ blˈuːpɹɪnt pɹəvˈaɪdᵻd ɪnðə kˈɑːmɪk bˈʊk ˈɪʃuː hˈæʃ wˈʌn ʌvðə sˈɪɹiz æz pˈʌblɪʃt baɪ mˈɑːɹvəl kˈɑːmɪks, ðɪ ɚɹˈɪdʒɪnəl ɪŋkɑːɹnˈeɪʃən ʌvðə bˈeɪs ɪz fˈaɪv lˈɛvəlz dˈiːp.
According to a blueprint provided in the comic book (issue #1 of the series as published by Marvel Comics), the original incarnation of the base is five levels deep.