In our house, not only are the humans interested in architecture, but so is one of the cats. Swan, who is about eight months old, has recently become a precocious architect.
For the past couple of months, Swan has built a number of little houses all over our house. This week, he is actually working faster than the demolition crews (a.k.a. Michael and me) can dismantle the homes.
Swan starts his construction process by knocking over a box, trash can, recycling bin, or paper shopping bag. He then goes in to the shell he has created and removes all the material inside (gut rehab style), sorting out all the scratchy things from soft things like plastic grocery bags. He then puts all the soft things back in to the box, sometimes taking the extra effort and importing plastic grocery bags from other parts of the house. When the house is complete, he moves in. He does a pretty good job of defending his property--the other cats are generally afraid to go in, and when they do he puts them in their place.
Some might argue that Swan is only lining cardboard boxes with plastic, and that is not a house, but I would submit to you that his cardboard boxes lined with plastic are not all that different in quality than many suburban-style homes being built in the region today!