Man-made underground passage in Streamstown (leitrim By.)

No stonework is visible, but a hidden L-shaped chamber stretches more than twenty-five metres inside the rath. The main tunnel runs north-northeast for fourteen metres, then bends east-southeast for another eleven. Someone dug through solid earth without leaving a single stone behind. The chamber may have been a passage, a cellar or a chamber for ceremony. The missing walls suggest the site was altered or erased after it stopped being used.