Best cat tree ever. I was looking for something to hide the litter box and this one is perfect. Hubby unscrewed the circular attachment tunnel at the bottom and set it in the S curve. Now the litter box fits underneath and all you notice is the tower and not the litter box. Kitty hangs out on this tower everyday and sometimes I find her sleeping in the "penthouse" and other times in the mid-section. She LOVES it.