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Greenhouse, Conservatory, or Glasshouse, are the terms often used to describe the name of a large building with a transparent ceiling, often made of glass or transparent plastic, which is made so plants can grow inside a closed space while still getting the sunlight of every day, while also being protected from the dangerous environment, which might include snow, ice, cold winds, and plagues, perhaps.
But how can we make it? I guess we can make the support out of wood. Still, we don't have any hardcore smithers nor forgers to make things out of metal, and it's not like we got anywhere to find metals unless we begin to collect them from around the ruins… and even then, it wouldn't be enough to make the pillars, so wood it will be.
And then comes the ceiling, glass.