Please post pics
Cat tree
(Not actually my cat tree but u get the idea)
Edit: i didnt generate this photo, its a link to an image that popped up. For the record, that would actually be a sick cat tree and I would buy it if it was available and I had the space for it which I do not)
The best one is definitely the box my computer case came in. It’s super sturdy, and the cats tear it up all the time and hide in it.