Next to a window that gets sun is a great place to put cat trees. Cats love sunning themselves, so this will be the perfect place for them to relax. Alternatively, cats often enjoy watching the world come and go from the top of the fort, so in a position that has a view of high traffic areas in your household is also a great option. Finally, don't place it anywhere that gives your cat access to breakables, such as near hung picture frames or next to the shelving unit where you keep your wine.