This is where the Riddler kidnapped Harley Quinn and Batman, suspending them over vats of acid and forcing Joker to choose between them, although this was all a ploy orchestrated by Poison Ivy in order to prove to Harley that the Joker did not love her. This is also where the Riddler filmed his riddles when he interrupted the regular broadcast with his threats to Gotham.
- "Til Death Do Us Part" (interior and exterior)
- "A Seat at the Table" (interior; flashback to "Til Death Do Us Part")
- "Harley Quinn Highway" (interior)
- "The Final Joke (exterior)
- "Dye Hard" (interior; flashback to "Til Death Do Us Part")
- The Sphinx is a well-known mythological creature who is infamous for handing out difficult riddles to her prey. Those who answer correctly are allowed to leave unharmed, but those who get it wrong will be killed and eaten.