ðə dˈʌbəlwˈɔːld ɹˈuːmz wɜː fˈʊli pɹətˈɛktᵻd ɐɡˈɛnst ɛkstˈɜːnəl θɹˈɛt ænd wɜː wˈɛl vˈɛntᵻlˌeɪɾᵻd baɪ ɹˈaʊnd vˌɛntɪlˈeɪʃən hˈoʊlz ɪnðə ɹˈuːf.
The double-walled rooms were fully protected against external threat and were well ventilated by round ventilation holes in the roof.