What's with Forts?

So the question of the day is, what is the reason that all children (and some adults) love to build forts? I remember as a kid making tons of forts. Of course now as an adult I can see how generous my Mom was to allow this activity in the first place since it always included using every pillow, blanket, and heavy object in the entire house. It usually consumed the entire kitchen table or most of the TV room and the couches. If I was really lucky and it was built to "code" and the "inspector" said it was okay, I was able to actually sleep in my fort for a night (not a fort night).
My children have recently discovered the art of forts. I am blessed with very smart, strong, children though, so their forts don't just use every pillow, blanket, and accessory in the house, but they included turned over furniture as well. Ethan and Kaiya had been very quiet for quite some time and I decided to peek in and see what the attention grabber was. Well, here is the carnage of Kaiya's room. I have to admit, it was structurally sound, optimized the light coming in from the south, and provided plenty of food storage (which I am still digging out of the carpet). There were books and activities and even extra bedding in case a friend wanted to come visit. My only concern was that Kaiya's bed was now on its side and the east wall was her mattress. These photos were actually before the final blanket walls were installed and I believe that the electricity was installed shortly after I found enough batteries for the flash lights. Wow, now that is what I call ingenuity. Now if I can get them to clean up these forts when they are condemned I will be doing good.
We are also the proud new owners of a new family vehicle. If you can't tell from the photos, it is a firetruck (duh). It even has a cardboard steering wheel and stereo. It only took 2 rolls of painters tape to get it to stay together. Good thing we are loaded and can afford endless amounts of batteries and painters tape. :) Porter was happy because once the new bedroom fort was built he was allowed to take over the firetruck and rip it to shreds.
It makes me happy to know that we can always tell people that we recently added on to our house and bought a new vehicle last week. They don't need to know it is a fort and a box. In my kids minds it is the best thing since cell phones (sliced bread is soooo last century).