This is a compilation of photos showing hollow galena cubes from Madan, in particular the Septemvri mine.
These have recently been found to be faked, an explanation is found in this article:

Exploration of the Hollowed Galenas

There is also a thread on the Mindat forum:
http://www.mindat.org/forum.php?read,55,157736,page=1


The photos have been removed from the locality pages, but they are still in the Mindat database, as part of the personal galleries.
Click on them to get to the full description.