Ironlock Prison

Ironlock Prision was constructed in 1543 (this date was given directly by NICOLE) and abandoned in 3134 (judging by the date given in Blast To The Past part 1, the “present” year would be 3234 and Nicole states that it was abandoned “100 years ago”).

Its general appearance is similar to a castle. An old wooden drawbridge spanning a gorge led to the the enterance, until Sally and Antoine caused it to fall into the gorge. Since Ironlock was abandoned, it has fallen into ruin. As such, it is dangerous to those who enter. Any part of it could collapse or fall apart with little warning. Inside, it has the general appearance of an abandoned prision. Some doors and cells are constructed of metal bars, while others are constructed of stone block walls and have reinforced wooden doors.

The computer that was used to leave a message for Sally was considerably older than than much of the Mobian technology that is shown in the rest of the show (Sonic even remarks that it looks ancient), and triggers a trap door when a rock falls on it, indicating that the computer could be over a hundred years old and was a part of the cell prior to the prision being abandoned.

Underneith Ironlock, is an old dungeon or sewer system, patrolled by a robot disguised as a reptillian monster. The walls and ceilings in some of the tunnels connected to this area are metal, and those tunnels are lit with soft red lights. The tunnel systems and underground caverns lead to areas in Robotropolis, allowing for escape routes and making infiltration easier.