What is the name of the Riddler's hidden trophy room in Batman: Arkham City?

The name of the Riddler’s hidden trophy room in Batman: Arkham City is Riddler’s Lair.

It is the concealed headquarters where Edward Nigma, the Riddler, holds hostages and oversees the deadly challenges scattered across Arkham City. Batman gradually locates it by solving enough of the Riddler’s riddles and rescuing victims from his trap rooms.

The lair is tied to the Enigma Conundrum side mission, one of the game’s largest optional storylines. Completing the Riddler’s challenges ultimately leads Batman to the hidden location for the final confrontation with Nigma. The mission also requires players to explore many districts and use nearly every major gadget.

A common mix-up is calling the location “Riddler’s Hideout.” That wording is used descriptively in guides and walkthroughs, but Riddler’s Lair is the established location name. The Trophy Vault, Puzzle Box, and Riddler’s Tower are not the canonical name of this room.