The illustrations of O'Neill cylinders I have come across with so far allow unrestricted view through the whole tube. Some are more playful with topography but still, there is a visible end. Are there reasons that forbid to close off parts of the tube, lets say, by a wall of mountain?
I would like to have warmer, moister and colder, dryer climates (possibly even more variations) within one single cylinder, that feel "naturally seperated" instead of a greenhouse within the complex. I also would like to increase the surface area with a lot more topography, probably even hollowed out in some places.
(As a site note Isaac Arthur talked about using aerogel, an ultra light material, to use under such constructions, to make them less heavy. I'm rather talking about an illusion of mountain than a real mountain.)
Each section could have it's own way of lightsetting, with a "sun" in the centre, or indirect light embedded in the environment, a long tube of light, or lightpoles as in street light..
Well, I wonder what reasons could speak against this idea. Could they be worked around, or do they make the idea impossible?