Castle building was once almost a national pastime in Italy. There are hundreds of them all over the country, and many of them are gradually falling into disrepair. Not all of them are as spectacularly ripped open as this one, though.
You can see from what's left of the ceiling here that this was once a palatial building, covered in fine art and frescoes. There simply aren't enough rich people in the country to take over the running of buildings like this when the original owners die, and so they become abandoned relics.