Międzyrzecki Rejon Umocniony – Muzeum Fortyfikacji i Nietoperzy w Pniewie

Beneath Pniewo run the tunnels of a former fortified line, now visited as a museum of fortifications. The underground is also a winter roost for bats, discovered in 1974 by biology students from Poznań. You can choose a short, long, extreme or surface route. Opening hours run 8:00 to 17:00 in summer and 9:00 to 15:00 in winter.