I had an interesting thought. There are a number of Titan IV silos going up for sale lately, and I had the idea, would it be possible to install and properly ventilate a pool in such a location? That is to say, in one of the underground chambers, not above ground or in the silo launch stack itself, and then if it was, what kind of ventilation system would it need? Like say you managed to fit a 30'x10' pool with a steady gradiant from 3ft to 8ft deep somewhere, and just like in any other indoor pool, you need proper vaporlocking and ventilation, so I'm wondering if you'd need an extra big mining-tier venting fan, or a bunch of small ones, and depending on how deep, would it need fan repeaters to actually reach the surface? Are there already air circulation systems that can be isolated from the rest to serve that function?