This reminds me of the short story by Ursula K. LeGuin, "The Ones Who Walk Away from Omelas", wherein Omelas, an ecstatically happy utopia, depends for its existence on the torment of one single child, kept in a basement dungeon. Citizens can view the child any time they please. Some never do, some only once, some quite often. Some, very few, after viewing the child, leave the city forever.

https://en.wikipedia.org/wiki/The_Ones_Who_Walk_Away_from_Om...