In high school we were having growing pangs, and so several of my classes were held in temporary trailers that had been hauled onto campus for that purpose. They were serviceable and not particularly hostile, and arguably more modern than the existing classrooms we were using anyway.

Then I graduate and enroll in a cushy university (UCSD) and come to find out, they're also having growing pangs, and so in the middle of campus we found ourselves taking classes in Quonset huts. These Quonset huts were bona fide military surplus, though it was already 1990. https://en.wikipedia.org/wiki/Quonset_hut

The Quonset huts were extraordinarily different from the classrooms and lab facilities we used on campus; they were, of course, comparatively set out in the wilderness, and very rough accommodations overall.

However, I was a commuting student, and nobody was living in Quonset huts, so after our hourlong class was dismissed, I was able to retreat to the relative comfort of home, or the Theodore Geisel library.