vˈɪzɪɾɚz ɑːɹ ɐlˈaʊd tə wˈɔːk ɚɹˈaʊnd ðə tˈʌnəlz ænd tɹˈɛntʃᵻz ðæt ɹᵻvˈiːlz ðə sˈeɪfti fˈiːtʃɚz ʌvðə stɹˈʌktʃɚ.
Visitors are allowed to walk around the tunnels and trenches that reveals the safety features of the structure.