I got a job once doing the demolition work inside of a big old factory. I was basically hired to tear down everything, walls, ceilings, toilets and especially ducts. They wanted the placed gutted so that they could do a complete rehab.
I remember that I was working with a partner and we got the goofy idea of rigging up a swing off of one of the really high up ducts. We figured that once we put our body weight on it it would fall right down (hopefully not on top of us).
After we finally got the rope in place my buddy took a big running start and proceeded to swing all over the factory. That duct had incredible supports because it held both of our body weights as we swung on that thing all day. It eventually took 5 r 6 of us to pull it down. That part was a pain in the neck but swinging on it was a lot of fun. I was almost sad to see it come down