The 11th Dimension was a dimension originally going to be in Crash Twinsanity, but it was cut from the final version.
Its origins remain a mystery. The canyon level would possibly be located somewhere here.
Upon getting back to the Iceberg Lab with Nina from the Academy of Evil, Cortex tells us a development 'joke': 'It was going to be two dimensions, but we ran out of time'. Stating that the game was rushed, and there were going to be two dimensions, but the developers ran out of time.