燕子口 Swallow Grotto（Yanzikou）

為太魯閣峽谷的一段大理石峭壁，峭壁有許多小洞穴，是由河流與地下水長期侵蝕所造成的壺穴，因常有小雨燕、洋燕在峭壁間覓食或築巢，形成「百燕鳴谷」的奇景，因而成「燕子口」。

This part of Tailuge (Taroko) Gorge is composed of marble cliff faces covered with small holes, the result of long-term erosion by river and ground water. House swifts and Pacific swallows often forage and nest here, giving the place its name.