underground structure

man-made underground structure

en-GB/ˈʌndəɡɹaʊnd ˈstɹʌkt͡ʃə/
en-US/ˌʌndɚˈɡɹæʊnd ˈstɹʌkt͡ʃɚ/

カテゴリ：

architectural structuresubterranea