User blog comment:Dragonsblood23/The Connection/@comment-5264252-20140528041258

Here's something for you: Mirage Comics' TMNT exists in the same universe as Marvel and various Disney shows. TMNT's origin story actually followed the same origin story for Daredevil. Daredevil was blinded when he gets hit in the face by a radioactive canister after pushing an old man out of the way of a truck, which had the canister on it or something. Years later, Mirage Comics copied that same story (without directly saying it was Daredevil), only the canister fell into the sewers where it mutated the turtles. This means that at least the first generation of turtles would've been able to meet the Avengers (as well as the later two TMNT cartoon shows during the anniversary movie "Turtles Forever").

Phineas and Ferb had a crossover episode a while back with Marvel characters like Spider-Man, Iron Man, Hulk, etc. However, Kim Possiple also made a cameo appearance in one episode during a "Spot the Difference" marathon where Kim Possible was a "difference" in a scene. Kim Possible crossed over in an episode of Lilo & Stitch: The Series, which also crossed over with American Dragon: Jake Long, Recess, and the Proud Family.

So...yeah. :P TMNT exists within the same city as Spider-Man and Jake Long.