Fort Charles (German Blockhaus, Fort Carl) - remnants of the fort on Mount Bird (841 m) near Lisia Pass. Fort was built in 1790, on the orders of King Frederick William II of Prussia as a small watch tower on the border between Prussia and Austria. It had a crew composed of few people guarding the road to Radkowa (the way of hundred turns).
In the nineteenth century, the fort was abandoned and began to fall into disrepair. Until now, only fragments are preserved - remnants of the wall, door and window, stairs and viewing platform.
Inside the fort there is the courtyard (once surrounded by wall) measuring 10x14 m, with the stairs leading to the platform (viewpoint).