The ‘skarpa,’ Polish for ‘escarpment,’ was originally used for training. However, since it was closed down in the 1980s it has only been utilized by various contemporary Polish performance artists because of the unique structure and commanding design.
Update: After visiting the site (which was not too easy to find by coordinates) it appears the object was taken down about 5 years ago. People in neighbourhood office had pictures of demolition. It was taken down for security reasons.