The Baobab Modern Cat Tree in Eco-Friendly White Laminate and Black Mohair (Faux) consists of multiple platforms (six in this case, including the bottom and top) that can be used for different purposes. For example, if the tree were set next to the window, its platforms could server as cat window perches. It even comes with carpet inserts that you can remove and/or replace.
The reason this is an eco-friendly cat tree is that it is made of wood fiber that has been 100% recycled. It sits at five feet tall and comes with rubber feet. According to one of the user reviews about this product, it is incredibly sturdy due to the rubber feet on bottom. This same reviewer says the Baobab Modern Cat Tree is a great choice for elderly cats because the platforms are evenly spaced and easier for them to climb!