To save the Earth from annihilation, Wolverine went back through time to kill Henry Pym before he could build the artificial intelligence called Ultron (Age of Ultron #6). Accompanied by the Invisible Woman of the Fantastic Four, Wolverine arrived as Pym (then Goliath) originally examined the artificial construct known as Dragon Man (circa Avengers #41).
Following Pym's death, Wolverine and Invisible Woman returned to the present. But the divergent timeline that unfolded was no better than the apocalyptic reality they had hoped to prevent (Age of Ultron #7).
Led by Dr. Strange, the Defenders on this grizzled Earth included Thing, Star-Lord (from the Guardians of the Galaxy), Captain Marvel (formerly Wasp), Cable (formerly Cyclops), Hulk (with the mind of Bruce Banner), Colonel America (formerly Captain America), and Wolverine. The group operated out of Defenders Sanctorum (Age of Ultron #8), also referred to as Defenders Headquarters (Fearless Defenders #4AU).
In yet another time-travel attempt, Wolverine went back to stop himself from assassinating Pym. This time, Wolverine suggested that Pym follow through with his idea to build Ultron yet add a time-release program to prevent Ultron from one day devastating the world (Age of Ultron #9).
I would have liked to have seen more of the Defenders from this alternate reality before the timeline was more-or-less restored.