My two cats, age 13 and 3 were checking out their new tree house as soon as I opened the box.  Very easy to put together, did it myself in about 30 minutes !   They were a little intimidated at first with the height but I put them on it and before I knew it they were in the house up high and playing with the hanging mice !  Only one fits in the smaller round house but they both spend lots of time on it and enjoy looking out the window.  It is really nice for the price and I am very happy with my purchase !  Will order from these folks again !