underground utility tunnel with industrial cables inside of stausee mooserboden lake dam, kaprun, austria - 地底下 個照片及圖片檔電線, 隧道, 拱門 - 建築特色
a construction worker wearing a safety harness and hard hat with toolbox checks a large drainage pipe at a construction site. - 地底下 個照片及圖片檔建築地盤, 風險
ore transport machines in underground gold mine shaft tunnel. mining industry - 地底下 個照片及圖片檔礦山, 器材, 挖掘