Passage: In post-apocalyptic Chicago (though this is not revealed until Allegiant), survivors are divided into five factions: Abnegation, the selfless; Amity, the peaceful; Candor, the honest; Dauntless, the brave; and Erudite, the intelligent. All sixteen-year-olds are tested to determine which faction they are best suited for, but select their own faction at the Choosing Ceremony. Those who do not complete initiation become "factionless,” living on the streets.

Question: Where do the sixteen-year-olds choose their faction?
the Choosing Ceremony