My cat broke the highest level off hers. She jumps on it so much and so fast that it started getting loose, and one day it just gave in and fell right over when she jumped on it. This isn't even a fat cat I'm talking about - she's just under a year old and weighs about 7 pounds! Well, we put the part that broke on the floor, so she now has a condo and a small apartment on the side, haha.