The grate that covers the six meters deep prison cellar in the historical prison of the Panemune castle. The sculpture that covers it may be here for historical versimilitude, but I doubt it, because the castle houses an art academy, and this may be a work of one of the students. Other students' works are positioned throughout the castle, blending in with the historical exhibits.
The cellar is six meters deep, and the prisoners used to be lowered into it by ropes. Most of them were kept here for not paying their taxes.