2105 is the year in which Teenage Mutant Ninja Turtles: Fast Forward takes place.
The Ninja Turtles and Splinter arrive in the year 2105 due to a miscalculation made by Cody Jones on his invention, the Time Window. The mutant family learn that Cody is a descendent of Casey Jones and April O'Neil. Due to their work, alongside Donatello, O'Neil Tech was created, making Cody an extremely wealthy heir.
The Pan Galactic Alliance has been in charge of Earth since the late 2050s, thanks to Agent Bishop, now President Bishop, evolving the Earth Protection Force by making treaties with other planets; giving over 20 different races a home. Due to this fact, mutants no longer need worry about being seen in public.