Batman Arkham City Easter Egg - Scarecrow's Secret Room

Find the boat in the Industrial District by the set of cranes. Glide onto it and go to the hatch at the end of the boat. This may take a few tries, but you need to stand in the right spot with your cryptographic sequencer to crack the code to open the hatch (Note that the lock box cannot be seen while doing this). This is a max difficulty security code to crack. Once the hatch is successfully open, you can go inside. You'll see roaches crawling everywhere, an invoice to Johnathan Crane a.k.a the Scarecrow, and a tied up thug. Make sure you zoom in on the thug with your camera. Enjoy!